Yamaha SR250 SE Specs and Info (1980 to 1985)

Yamaha SR250 SE specs

The Yamaha SR250 SE was a commuter style 4 stroke motorcycle manufactured between 1980 and 1985 (ish!). With styling taken from the Yam SR500 and SR400, the SR 250 was aimed at the popular quarter litre motorbike market (in the UK we used to be able to ride a motorcycle up to 250cc on a car license without the need to take any further motorbike tests).
The SR250 was available in other countries and was called the SR250 Exciter in the USA.
The SR250SE proved to be (and still is) a popular and reliable commuter bike.

Yamaha SR250-SE

Need parts for your SR250? Find SR250 spares…

A little bit about the Yamaha SR 250 SE…..

Basic model info…

Manufacturer: Yamaha
Model: SR250 SE
Also known as (aka): SR250 Exciter
CC: 239cc
Engine type: Single cylinder (4 stroke)
Years in production: 1980 to 1985
Style of bike: Commuter
Insurance: Group 4 (of 17) – SR250 insurance up for renewal? Save money at Confused.com

There now follows a necessary but totally unrelated ad…..Sorry!


Yamaha SR250 engine
1981 Yamaha SR250 SE engine

Engine, gearbox and drive stuff…
Information: SR250 Service Manual
Yamaha engine code: 3Y8
Displacement: 239cc ccm
Engine type: Air cooled, four stroke, single cylinder, SOHC (single overhead cam)
Bore x Stroke: 73.5mm x 56.5mm
Inlet valve clearance (when cold): 0.05mm to 0.10mm
Exhaust valve clearance (when cold): 0.12mm to 0.17mm
Gasket: Engine gaskets
Recommended engine oil (4T): 10w40 Semi Synthetic motorcycle oil
Engine oil capacity: 1.3 litres (1.6 litres if the oil filter is changed as well)
Oil filter: Filtrex OIF018 / Hiflo HF145 / K&N KN-145
Compression Ratio: 8.9:1
Firing order: If your looking for the firing order you might want to read this book (hint, it’s a SINGLE CYLINDER engine)! πŸ™‚
Power: 20 bhp at 7700 rpm
Torque: 13.7 ft-lb at 7000 rpm
Standing ΒΌ Mile time: 16.3 sec
Cooling system: Air cooled
Gearbox: 5-speed
Clutch: wet (oil immersed), multi plate clutch

Note: You’ll need a clutch holding tool for removing it, a clutch lever if you’ve dropped it and possibly a clutch cable if it’s suddenly stopped working!

Final drive: Chain (chain and sprocket kits)
Drive chain length: 102 links
Drive chain pitch: 520
Front sprocket teeth: 16
Rear sprocket teeth: 45

Note: Some models had a slightly smaller, 15 tooth front sprocket instead of the standard 16 tooth front sprocket (if your replacing your old sprocket, count the teeth to see which one you have!)

Top speed: 89 mph….Ish!

Please note – The 89mph top speed was Yamaha’s estimated top speed (used on their marketing bumph!) back in the 1980’s. As with most marketing stuff, this should be taken with a pinch of salt (most manufacturers inflate the top speed figure in their marketing leaflets as it helps increase sales!).

Yamaha SR250 side/back
Side view of a (very scruffy!) 1981 SR250 SE

Carb and fuel stuff…
Carb type: 34mm Mikuni carburetor (carb parts)
Carb type: BS34-III
Pilot screw opening: 2 turns
Float height level: 3mm (+ or – 1mm)
Engine idle speed: 1200 rpm
Fuel tank capacity: 10.8 Litres
Average MPG: 70 mpg (miles per gallon)
Fuel tap: On the left side of the tank, behind the engine – Petrol tap repair kits

Yamaha SR250 carb and engine
1981 Yamaha SR250 SE carburetor and engine

Electric stuff…
Ignition type: Electronic CDI
CDI manufacturer: Hitachi
CDI part no: 3Y6 and TID11-02
Voltage: 12 volts
Regulated voltage: 14.8 volts (regulator/rectifier)
Ignition switch: Center mounted handlebar key operated ignition Switch
Plug coil primary resistance: 2.48 to 3.00 ohms
Plug coil secondary resistance: 6320 to 9480 ohms
Pick up coil resistance: 630 to 770 ohms
Pick up / contact breaker gap: 0.6mm
Max alternator output: 8 amps at 4000 rpm
Starter type: Electric starter motor
Battery: Yuasa YB12A-A
/ AC/Delco AB12AA
Spark plug: NGK BP7ES
Champion RN7YC
Spark plug gap: NGK 0.7mm to 0.8mm – Champion 0.8mm

Yamaha SR250 speedo
1981 Yamaha SR250 SE speedometer and warning lights

Exhaust system…
Type: 1 into 1 system
Gasket: 45mm (outside diameter) x 38mm (inside diameter) x 5mm (depth) exhaust gasket

Yamaha SR250 rear drum brake
1981 Yamaha SR250 SE back drum brake

Shocks, brakes and wheels…
Front tyre size: 3.00-18 (300-18)
Front inner tube: 275/300-18

Note: There seems to be a bit of confusion over if the SR250 had a 19 inch or 18 inch front wheel. The few we’ve had in all had 18 inch front wheels, but most tyre reference books say they have 19 inch front wheels (so best to check your old tyre before buying a replacement!)

Rear tyre size: 120/90-16
Rear inner tube: 500/510-16
Front tyre pressure (if your on your own): 1.8 bar / 26 psi
Front tyre pressure (if your carrying a pillion): 2.0 bar / 29 psi
Rear tyre pressure (if your on your own): 2.0 bar / 29 psi
Rear tyre pressure (if your carrying a pillion): 2.3 bar / 33 psi
Front brake: Drum (expanding) brake (front brake lever)
Front brake shoe: EBC Y511 / Vesrah VB-220
Rear brake: Drum (expanding) brake
Rear brake shoe: EBC Y506 / Vesrah VB-223
Front wheel type: Spoked wheel (front wheel bearings)
Rear wheel type: Spoked wheel (rear wheel bearings)
Head bearings: steering head bearing kit
Front Suspension: 32mm Telescopic forks (fork seals)
Front fork oil type: 10w (medium weight)
Front fork oil amount: 168ml (per fork)
Rear Suspension: Twin shock (with preload adjustment)

Yamaha SR250 front drum brake
1981 Yamaha SR250 SE front brum brake

Weights ‘n other stuff…
Wet weight (inc oil, petrol, etc): 122 kg
Tachometer: Cable operated
Speedometer: Cable operated

Useful tightening torques…
Cylinder head (1st stage): 37.5nm
Cylinder head (2nd stage): If M8 bolts, 20nm – If M6 bolts, 10nm
Magneto / flywheel: 80nm
Camshaft sprocket: 55nm
Crankshaft sprocket: 70nm
Clutch hub: 70nm
Spark plug: 20nm
Front wheel spindle: 106nm
Front wheel spindle clamp (the ones in the fork leg): 22nm
Rear wheel spindle: 106nm

Yamaha SR250 front view
1981 Yamaha SR250 SE front view

Other stuff…
Although the SR250 SE was never going to set the motorcycle world alight and wasn’t really all that much to look at, the bike proved very popular with commuters, people looking for their ‘first big bike’, younger riders, city couriers and people looking for a winter hack. Good Yamaha build quality and a fairly bulletproof engine means there are still a fair few around (meaning they are also cheap to pick up now, usually under Β£500 for a good, road ready example!)

Buying advice…..
As with all Yamaha’s of this age, the electrics can be a bit corroded and problematic (especially in the rain!).
Also, the metal and chrome parts will have seen better days, a bit of rust around the tank, forks and chrome parts is common and nothing to worry about but watch out for bad rot, especially on the exhausts and forks as finding good and none bank account emptying exhausts and forks can be tricky!

Motorcycle Specs

The Yamaha SR250 SE specs and information on this page are correct to the best of our knowledge. But the info should NOT be taken as 100% accurate as we can, occasionally, make mistakes (despite rumors, we are only human!!)!

To keep this page as a free resource for people to use, there are affiliate links (mainly Amazon) throughout the article. These affiliate links help maintain the cost of running this blog (basically, if you visit Amazon through one of the links and buy something, we make a few pence!).

If you have any 1980 to 1985 Yam SR250 questions, please post them below πŸ™‚

201 thoughts on “Yamaha SR250 SE Specs and Info (1980 to 1985)”

      1. I’ve had a 1981 for about a year, and even with a little fairing added, I’ve barely seen 80mph with a tailwind. More like 75 on a calm day. πŸ™‚ I am about 200 pounds, so maybe with a lighter rider, you may see that speed!

        1. Got an ’82, I’ve seen 80 once, front end is unbearably wobbly at that speed, but all on all a great little bike

      2. I have a 1982 yamaha sr250 exciter body style is bc. I have lost almost all compression and was wandering if you know what all could cause this also the valve that you can see open and shut through the spark plug hole is squeaking is there any advice you can give to help me out so i can fix without a costly repair bill from a shop? Thank you for your time.

          1. Iv got all parts to fix iv got all valves rings and gaskets how would i get the specs for the 82 yamaha sr250 exciter bc would you happen to know

          2. How would i get to the top of the valves there under the rockerarms how doi get around them to get to the valves?

    1. I got distracted and caught myself doing 75 mph on my 1980 model just the other morning. Whoa there, big fella! What a great bike.

    2. I have the SR 125, I am quite a heave guy and can get it up to sixty πŸ™‚
      This is my first road bike up till now, have always had scooters before. I would like the SR 250 once I have passed my full bike test! Have also thought of putting the 250 engine into the 125. There doesn’t seem to be many sr 250’s going about the UK. Are the mostly imported now due to the licencing changes in the 1980’s when u weren’t allowed to ride a 250 on a car licence anymore?

      1. Yep, 250cc bikes sort of died when the driving license was changed, but they are still popular in the US, Japan and some other countries (although some major manufacturers still make and release 250cc bikes in the UK).

      1. As standard the bike should easily be able to to 2000km with odd stops for fuel and possibly stopping for a break every 1.5 hours to let the engine cool down……….But it does greatly depend on the condition of the bike and engine (tyres, bearings, cables etc).

  1. What a great blog. I have this bike, the SR250 SE, to commute to my local station every day. It’s incredibly reliable and I don’t get traffic backed up behind me – not that it’s fast but I can still get it up to 50mph. I cannot believe it runs so well and it’s over 30 years old. I did some dispatch riding in London during the late 80’s on a Honda CX 500 – an incredibly reliable beast. For me this 250 is a great little machine – mine says “U.S. Custom” on the side panel – what does this refer to and what’s the 400 was like?

    1. Yep, the Yam SR250’s are good and reliable bikes (which is one of the reasons there still the staple diet for commuters in Asia!).
      I’m fairly certain the SR250SE and the SR250 US Custom are almost identical (except the side panels). The ‘US Custom’ bit may have come from some SR250’s imported to the UK (often bike models will have a different name in other countries, e.g. the Honda NT650 was called the Revere in Europe, the Bros in Japan and the Hawk in the US).
      If you look at pictures of the 2 bikes side by side it’s very difficult to spot any differences.

      Although the SR400 is similar to the SR250, the 400 was a smaller version of the SR500 (the SR 400 had a slightly different crank shaft fitted to reduce the engine stroke and CC).
      The SR400 also has a disc brake on the front (instead of the SR250’s drum brake), a bigger engine, larger tank, slightly wider tyres, different (flatter) seat etc. The SR400 also has slightly different styling.

      The SR 400 isn’t anywhere near as common as the SR 250 (the SR400 wasn’t an official bike in the UK, only a grey import) so spares aren’t as readily available for the 400 as they are for the 250.

      Apart from the above I can’t really say what the SR400 was like, mainly because I’ve not ridden/owned one!

  2. When I baught mine in back in 1980, the SR 250 SE Special was the cheaper single, the other one was based on the XS 250 twin with the US Custom on the side panels. A mate at work had an ordinary XS 250 & had constant trouble with the points closing & timing slipping so I was glad I got the single. Mind you, now it’s its my turn with ignition hassle. I can get a brand new Boyer eletric ignition kit for my ’72 Commando for Β£73.80 rotor, stator & box, but buggered if I can find a CDI unit for the Yam!

  3. I have a 1981 sr250, and recently bought a 1980. They’re only months apart in age. I bought the second for compatible spare parts. Was I correct in assuming they’d be compatible? Unbolt from one and simply throw onto the other? I’m Australian based, Melbourne. Enjoying the discussions, thanks.

      1. Hi there, am buying an old sr250 from another city, the seller has found the engine ID on bike, but he is unable to locate the frame ID? Can you tell me where he should look?


  4. Any Idea where I can get workshop manual for SR250 1981. Does the CDI system need a battery supply & if not how does the ignition switch work? Any help greatly appreciated.

    1. Yam SR250 manuals do seem to be hard to come buy, but there’s a few for sale on Ebay (although there in the USA)?

      You might be able to get one by asking on a Yamaha SR250 forum:

      Google search for SR250 forums

      The SR250’s do bump start (if the batteries flat) so I’m guessing they don’t actually ‘need’ the battery to run. If you have one the easiest way to check is to start it then disconnect the battery, if it stops it probably needs the battery.

      In very basic terms, the ignition switch is just an ‘on/off’ switch for the bikes systems.

      1. Thanks for your info. Its really the wiring diag I’m after as most of the wiring has been disconnected. It seems to be a CDI ignition, I’ll keep at it!

  5. Wow this is pretty recent. Just bought a 1982, this is the US edition mind you. I have a ton of questions, but I really wanted to ask anyone about gear ratios?

    It seems with what I have on right now top speed is about 65ish (with it redlining). What gear ratios are you guys running to get up to about 75-80MPH?

    Also, with it being such an old bike (mostly tooting around old people to the office most its life) it has GOT to be gunked up somewhere? Where are some main areas that get dirty on these bikes? Carb? Air filter? Points?

    Speaking of points……… Does anyone have a manual on adjusting the timing?


    1. run a bottle of Sea Foam through it that will probably work this is a simple bike very low maintenance just get on and give it hell she will take it. as far as a manual you can find it on line cant remember where just google it. as gears go sounds like maybe it was changed out once before or something but i got more top end speed with a bigger rear gear and stock front gear. These bikes will take high revs for long periods so you are probably not redlining it a, 1 cylinder just sounds like it kinda like a dirt bike.

      1. A bigger rear sprocket lowers the gearing and would make it, the bike, slower for more speed you would have to put on a larger front and smaller back sprockets

  6. have an sr250 drilled out the main jet, cut of the baffle and to a straight pipe. I am 240 lb man and this ike does 90 mph regularly or until cdi says different.

    1. hi Mr Hustle, what drill size did u use? i have a the sr250 and having stuttering problems mid to top range was thinking i need a jet kit but if i could drill it all the better.

  7. I had an “81 SR250 as my first road bike got great mileage and I did do some long trips (for a 250cc) with it. changed out the air box for pod filter, little bigger rear sproket and drilled the baffles and she would do 100mph with me (180lbs) on it. Was a fun bike wish I still had it for an “around towner”. Would buy another one.

  8. Hi all, I’m hoping to change my block shaped speedo/warning lights console with a smaller, cylindrical speedo (whether with or without warning lights is another issue). But all my research is dizzying! Gear ratios, Virago speedos that may or may not inter-change.
    I’ve found that a SR250 speedo ratio is 100kmph/ 2330 rpms.
    However I’ve also found that at 60kmph/ 1400rpms. What should I look for to change my Speedo to a compatible other design?

    Are both these correct merely relating to the differing speeds, or are they wrong.

    I came back to this blog. Thanks so much for the great info previously. For someone like me who’s only mechanical experience was pulling my wrist watch apart, I’m having fun with my sr250s. Seems they do keep going even if I get to them πŸ™‚ .

    1. As a general rule of thumb, as long as the front wheels are the same width the speedo should read the same with no mods needed. So as long as the speedo came from a Yamaha bike with an 18 inch front wheel it should* work fine (*=I say ‘should’ because nothings perfect! πŸ˜‰ )

  9. Hi guys, Letting you all know what I ended up doing regarding a cylindrical style Speedo rather than the original block combo of indicators, Beam …. I read on a Blog somewhere that a chap used a Virago Speedo. So that evening I found one on Ebay for 49$. Easy, looks great and works great. Thanks for your continuing guidance WhiteDogs.

  10. hey there, never really had an interest before but the past few years, i’ve been wanting a bike…maybe it’s mid-life crisis at age 46. So i stopped in to visit a neighbour last weekend. There it was, a 1982 Yamaha SR250J that I learned he bought in ’91, never plated it, just drove it around the yard. Put it away in the shed in ’92. But there it was, sitting there ready to go for scrap. Wow, I thought. I went over to look at it. It is complete but in rough shape, surface rust everywhere. Tires are not weathered but the rubber is hard. Long story short, I bought it for next to nothing and had it home that afternoon and started its revitalization. The piston was ceased and freed up easily and the carburetor needed a tear down and good cleaning. The carb is like a showpiece. The gas tank was filled before parking, so I’m not sure of the inside because the cap won’t unlock. I’ve spent the last 5 days cleaning this thing up to a point of starting it. The seat is showroom condition. I do believe it will start. We’ll find out tomorrow. I hope to make this my summer commute vehicle.
    Any thoughts on what else should be done to this old gurl ?

    1. Good on you for resurrecting the bike! I would say try and get in the tank and have a look before you start it (the tank could have loads of rust and dirt in it which could block up your fuel tap and carbs). You can spray a maintenance spray grease into and around the lock and leave it to soak for a while to see if it frees it up?

      Also, depending on how long the fuels been in there it might be best to drain the old fuel and replace it with fresh petrol.

      Apart from the above, the only advice would be to grease/oil everything up before your 1st ride and check all the important stuff (like the brakes!) work.

      Have fun on it!! πŸ™‚

  11. howzit i recently bought a 1996 SR250 and i am really enjoying riding it. it does 110km an hour comfortably.
    i also want to learn to do the maintenance myself
    i think the oil is over full and would like to learn to change the oil and oil filter. any advise regarding oil pressure would be good.
    i enjoy reading your blog

  12. looks like i joined the club. picked up a sr 250 in august. what a great little bike. only problem is a leak on the left side of the case (i think it’s a sproket seal gone bad).
    other than topping up the oil every once in a while, what a great commuter. serving as a second vehicle right now, hoping to ride it till the beginning of december (i live in the great white north).

  13. Recent joiner as well. Just got my 1980 SR250 registered. I too have a drip on the left side of oil that I haven’t bothered to investigate yet. Fun bike.

  14. Just a thght.
    Do you think a respoked front sr250 rim with accompanying tyre to go as a back wheel would … handle it?
    The really early bikes had same sized wheels … same sized THIN wheels.
    mmmmm I was just thinking. Thoughts?

  15. Hi ya WhiteDogBikes, hope you guys, and everyone had a great new years 2013/14.
    I’ve got a prob in that just prior to a great mbike tour with some mates, I adjusted my intake and exhaust values, put in some oil … basically a soft servicing. The road we travelled … holey geez I tell you, it was rough patched up roads for a good part of it. Shook off a few bolts lterally on all bikes, but it also shook out the intake adjuster valve screw and hex nutt. No wonder she ran really bad the last 400km! πŸ™
    Where’s my adjuster valve screw and hex nutt?
    The thing hasn’t exploded, and got me home. So what do you think? Will I have to remove the cylinder head to find them?
    Oh man, I know I sound really stupid, but I’ve been dong my own mechanics on my bike now for some time, never having done any mechanical work before. I’m really happy with my efforts. Except for this!

    Thanks if you can suggest anything. Bye.

  16. O.M.G! I have got to be one of the dumbest, but luckiest dim-wit about, or this is common place and due to my lack of knowing … ANYTHING about mbike engines, I don’t know about it.
    I rode for 400km at full throttle, topping only 78kmph (with headwind), then with a tail wind change, I managed 84kmph. Noise from the engine like you have no idea.
    It turns out that my inlet adjuster valve screw and hex bolt had worked their way loose and off.
    This baby got me home regardless, as per my earlier posting. I’ve since searched the net for info, any info. All I managed was learning new, correct terminologies for the parts of my disappointment and cluelessness.
    With nothing to lose, I simply opened both inlet and exhaust valve covers (you see… I now know their right names) and had a look. THERE, sitting in a bit of oil was my inlet valve adjuster screw right in front of my exhaust valve chamber. I alligator-pliered it out. Then, feeling lucky (but still clueless), I looked around and located my hex-nutt down deep below my inlet valve chamber.

    Get stuffed! How can this be?! Anyway, I’ve managed to screw them back into place. The Inlet Valve Rocket appears to have far too much … ROCKING in it now. You guys probably already know what that means. So I’m off to discover it for myself. But I plan on kicking her over now (you guys probably know what that will end up as too! … but contain your laughter, I’ll be back!) πŸ™‚ [happy for now], Marco

    1. Happy new year to you as well, glad you found the parts.
      If it happens again (or something similar!), try and find the missing parts if you think there inside the engine before moving on as loose metal parts inside the engine can often result in major damage!

  17. My speedo on my 82′ is not working and im not sure why unless its the wiring but i just got into bike and am not sure what all to check came across here and was wondering what all it could be.

    1. If you disconnect the speedo cable from the back of the speedo you can remove the inner cable and check it’s not broken?
      Also, if you remove the speedo drive from the front wheel (it connects to the other end of the cable, on the side of the front wheel), check it spins smoothly and freely. If it doesn’t spin or spins very roughly / jerky, it may need replacing or a very good strip and clean (these are the 2 most likely reasons for the speedo not working).

  18. Hey everyone. I’ve got a few problems with my 1981 Yamaha SR250. First off, It lags? When I’m going about 5-15 MPH and give it full/half throttle in first gear it lags for like 1-2 seconds. What do you think that is about? And in second gear from 18-25 mph it lags when full/half throttle is given. And does the carb have a fuel/air screw?? If so where is it located? This has happened to me a couple times lately, all of a sudden I go to give it throttle and it dies! Then start it back up, give it some throttle and bam its dead and dieing. I thought hey i’ll check the spark and there was a light yellow spark. So, I took the coil wire off and inspected it, put it back on and everything was back to normal, and the spark was a nice powerful blue spark. I have a prolly a 4 week old spark plug and a week old air filter. Other than this though it runs great. Thanks everyone! Happy riding!

    1. The carb will have a fuel/air mixture screw (it should be easily visible on the side of the carb). Your lagging problem could be a dirty carb (you could try running a good fuel cleaner through it or take the carb apart and give it a clean). Could also be faulty electrics (it might be the wires degrading inside the coil or HT lead).

        1. There should be 2 screws (I think?), 1 will be the idle screw and 1 will be the fuel/air mixture (unfortunately, I’m trying to work from memory as I don’t have an SR250 carb to check!).

  19. Ok I think I see what you mean! If I can email you I’ll send you a picture of the screw I think it might be so I can confirm it. I don’t wanna start twisting and mess something up without knowing for sure! My Email is XXXXXX@XXXX.com. I would appreciate it if you would email me. Thank you sir!

    1. You might want to check your junk mail box as I’ve now sent the email twice. Our email address is on the top/right of this page (in the blue bar across the top)

    2. Turns out I may be wrong, the fuel/air adjuster screw might be on the engine side of the carb. There should be little hole in the top that you put your screwdriver down and the screw is at the bottom of that hole.

      Source: http://www.yamahaclub.com/forums/topic/26513-sr250-air-mixture-problems/

      As a general setting, screw the screw in so it’s lightly seated and doesn’t easily turn in any more (lightly though, don’t force it!), then back the screw out 2 full turns and see how it runs (if it doesn’t run well try backing the screw out a quarter turn at a time till it runs ok).

      Due to the age of the bike, your carb will probably need a good take apart and clean though…..

  20. Can anyone tell me how to change the fork oil? Every time I do a search, it only pulls up information about the fork seals. I know where to drain the oil but when I remove the cap that I thought covered an access bolt, there is nothing there.

    1. You should be able to drain the fork oil by removing the bolt from the bottom of the fork (you should be able to see it if you remove the front wheel spindle, it’s usually a hex socket bolt, you may need an impact gun to remove it). There’s also a small screw on the side of the fork, just above the spindle hole. This may be to let the fork oil out (although I’ve never removed this screw so can’t say for sure!).
      To fill the forks, remove the big bolts in the tops of the forks and put the oil in (best to fill 1 at a time).

      There’s a good part diagram of the SR250 forks on the page below:

  21. I just purchased a Yamaha 250 . It was sitting in a garage sense 1984 . After cleaning it up and changing the oil I have tried to start it and I am not getting spark. What could be the most likely reasons for this? The bike only has 1543 original miles on it

    1. If it’s been stood for so long, you should probably change the spark plug so you can rule out the fault being from a bad plug.

      Also, check the spark plug cap is clean and properly screwed on (these can be loose which causes a bad connection) and look for any damage or splitting on the HT lead (the thick, black lead that runs from the plug to the coil).
      You can also check the wires coming from the coil and the CDI and look for damage or excessive corrosion, also check the earth connection from the battery and other parts are undamaged, corrosion free and properly attached.

      1. Hi I found one of these gems on FB for sale .. it needs some Love I’m 5’9″ and about 220 do you think this would be a good starter bike for me ???

  22. hi.i have an sr250 bt im not quite sure which year it was made so as to base my question on.the bike has quite some noise coming from the engine(the black painted part), like a cranking sound or something.i asked 2 guys about it and one said it might be a loose camshaft and the other said something about a worn-out chain guide.i really like the bike pliz help.

    1. A worn out cam chain guide (or worn can chain) would normally be a rattling/chattering type sound. To be honest, I’m not sure what you mean by a ‘cranking’ sound?
      How many miles has the bike done and do you have any service history for it (e.g. was the cam chain changed if the mileage is high?).

      I can be difficult to diagnose engine noises over the internet, it might be worth while you taking it to a proper motorbike garage to get a professional opinion?

  23. Mr WhiteDogBikes,i think you are right coz the sound is more like rattling/knocking inside the engine and it used to increase when i revved the engine whilst in neutral bt now its audible even when travelling.i bought the bike last year from somebody who got it from auction in 2012,and the guy did the service himself.what im quite sure of is that the bike has been lying idle at the auction floor since 2007 til the guy bought it .i’ve looked on several blogs for an answer bt am hitting a dead end.the bike was ok all along til last month when the sound started.i’ve since parked it coz of fear i might further damage the engine.i also dont know whether what those two guys said was true about worn cam chain guide/cam shaft.the bike did 35000km and the two guys said the cam chain was ok.

    1. If it’s a rattling noise coming from the engine, it could be the cam chain or a worn cam chain guide or the cam chain tensioner?

      Might be an idea to drain oil and see if there’s any metal parts in it (this would indicate something being badly worn!).

      Only way your going to find out really is if you take the engine apart or take it to a garage….

  24. Hi guys I picked up a 1994 sr250 2 weeks ago, I’m sure it’s an import as well. I will be changing the oil and filter this weekend with 10w40. I also want to clean the air filter ( can I use 10w40 oil for this??) And today after going a bump in road the bike felt like it was grounding and felt different like it was grinding the road, any clue as what this might be? Thanks

    1. You should use a proper air filter oil (or an SAE30 oil) for the air filter. If you’ve hit a bump and it’s changed the handling, have a look for any visible damage to the rear shock, front forks and wheels (are the fork seals leaking now, are there any dents in the wheels, are the wheel bearings still ok etc).

  25. Hey! I found the air/fuel screw and got that adjusted. You have to get a plug out on the engine side of the carb. I’ve got a couple new questions though. What kinda rear shocks does the bike have? And next, how do you get the fork seals out? Are they easy to replace? one of mine blew and I don’t see me self paying the dealership $200 bucks for their time. Do you have to replace the dust covers? Oh and last thing. where you take the forks off theres 2 bolts that holds them on, but theres a rubber thing over them? how do you get those off?

    1. The SR250 has twin rear shocks with preload adjustment on them.
      If you’ve not done it before, you would be better off asking someone to show you how to change the fork seals as it’s a bit too complicated to explain on here? There were some videos on YouTube showing how to change the SR250 fork seals last time I looked.

      Personally, I’d replace the dust caps as well (there not too expensive).

      Not sure what you mean by the rubber bit covering the bolts (if it’s an aftermarket part I’d imagine it just pulls off?)

  26. Hi my name is tina hi everyone. I bought my sr250h in oz 3 yrs ago I love it its in exellent condition for its age but I think it needs new starter motor brushes i do maintenance on my car myself so was gonna have a go at fixing it myself. Ive checked the battery thats fine so definitely starter motor issue but can anyone tell me if I have to take both covers off to get to it?? I may be able to remove it from left side but then I think the running gear will drop and that I will have to remove right cover to put it back is this the case?. So does this mean draining oil etc??? I would appreciate any help you can give me thanks Tina

    1. I think you may have to remove both cover to get to it (I’ve not removed the starter from an SR250 so can’t be 100% certain though!).
      Might be worth looking on YouTube as there seems to be a fair few people on there who’ve made videos of them striping the engines?

  27. Thanks for your advice I did have a look on youtube but couldn’t find anything on starter motors but I will have another look see what I can find thanks again

    1. in case you didnt already figure out, you do have to pull both covers off, so yes oil draining. ive got a 1980 that didnt start electrically when i bought it (push started it for like 6 months before i found a kickstarter assembly from a tt250 at a scrapyard -_-) but i did try to take the starter motor apart to see what i could do. took it out from the left side not thinking about the gear and it dropped into the right side case. put it back together (couldnt get the starter to work) and couldnt figure out why it seized for a day or two before i took it apart and found the gear chilling on the right side

  28. Thanks man! I ajdustested those shocks and man does it feel better. So glad I don’t have to buy new shocks!! About the forks though. Theres lots of videos on youtube but only one on youtube about the forks for the SR250 that I could find. And he doesn’t really show you how to change them. If you could help me find a video closest to the 250 forks and really explains how to change them I sure would appreciate it. You sure have been a good help! Oh and last question. Do they sell aftermarket SR250 fork dust covers? I couldn’t find anything on ebay. Thanks a lot! Hope your having a good weekend!

    1. Just did mine on an un-loved 1980 I’m restoring. NOT for a novice! Don’t even bother if you don’t have lots of time, patience, some experience and tools. The first challenge was to get the spring clips out of the fork tops, or even find them so rusted were they. Anyhow the fork caps had to be cold punched down where they promptly seized. Spring clips out, top pinch bolts loosened. Had to drill and tap holes in the seized fork caps then fabricate a puller to get them out, they were stuck in there but good.
      Drained the 35year old oil. Made an 8mm hex tool by chopping off the short end of the L shaped hex wrench to fit the 8mm socket for my electric impact wrench. One spun but didn’t come out (expected), one wouldn’t even budge with impact. Required a little heat and tapping with brass mallet. Had to fabricate a 2.5 foot long 8mm steel bar threaded on one end with a 14mm nut brazed on to help hold the damper rod ( it handily has a 14mm hex female at its top). Forks finally dismantled! Next pry those old seals out, bent 3 big screw drivers. Fold a leather glove and put it between lever and fork mouth otherwise you’ll damage it. In the end what worked was a large hardened steel punch with a cheater pipe. As I said…not for the fain-of heart but maybe yours will go easy on you! New seals in. Used slightly modified circlips instead of the rusted ( and discontinued)wire clips to retain the seals. Clean everything with steel wool, brake cleaner and plenty of rags. Reassemble in reverse with 10W forkoil. Good luck all.

  29. Hi I own a 1982 sr250 and two days ago chain came off while shifting to 2 gear. I managed to get chain back on but now it wont start on neutral and the indicator light for neutral wont come on. It starts on 1st then it can idle on neutral but only with kickstand up. This is the first time this has happened
    Any thoughts on what it could be? Thanks

    1. Is there any damage or disconnected wires around the bottom of the engine, near the side stand or around the gear pedal?
      Sounds like the chain may have caught or damaged a wire when it came off.

  30. How do I install new chain on my 1982 sr250? I bought one on ebay but all links are connected and it is my first time doing this. do I need special tool fo this? Manual I have doesnt mention this. thank you

    1. If it’s a complete chain, you’ll need to remove the back wheel and the front sprocket to fit it (also possibly the chain guard?). Getting the chain tension correct is very important (too loose it can come off and damage the bike, too tight and it can bend the crank or snap!), so if you’ve not done it before you might want to get a friend to show you.

  31. I’ll have a look at the wiring thanks I intend to change chain for one i bought on ebay. Do i need special tool for installing new chain,? This will be my first time. Oh yeah went to the shop and was informed that dry wax lube on chain is a terrible thing it needs grease. I think that might be why chain came off as well as the fact that the tension needs adjust. Don’t know how to do that either…Well I love this bike I use mostly for commuting locally but have ridden her as far as Richmond on the interstate from virginia beach. So I will try to keep her going. Your thoughts are much appreciated.

    1. Your chain most likely came off due to being too loose. With chain lubes, some people prefer waxes, some people prefer oil based lubes, the MOST important thing about lube is to use it ‘little and often’. I’d lube the chain every other day if your using the bike daily.

      Getting the chain tension correct is very important (too loose it can come off and damage the bike, too tight and it can bend the crank or snap!), so if you’ve not done it before you might want to get a friend to show you.

  32. easy got the chain adjusted figured out how to do it without having to touch the chain itself . thanks for the advice.

  33. Hello from Australia!!
    Iv’e thoroughly enjoyed reading the old entries as i started playing with my new toy (1982 SR250J) and stripping it down to get ready for painting.. Its been super helpful with some of the issues I’ve run into so far…
    I was hoping someone here would be able to help me find out the wiring codes and possible a full wiring diagram.. The previous owner has cut and replaced a few wires and I’m not 100% sure on why…
    Cheers.. πŸ˜€

    1. You should be able to find the wiring diagrams in a service manual for the bike (the example below is in the US but they might ship to Oz?):

      SR250 J manual…

      Alternatively, I think there’s a few Yamaha owners forums on the net, someone there might have the wiring diagrams?

  34. Hello from Washington state!
    Just picked up a sr250 to teach the ol’lady how to ride! I’m looking for parts, and I can barely find anything for this antique! I need piston rings and all sorts of goodies! Been on ebay, found some stuff. I wanted to get a new piston, and was wondering what the exact piston diameter is for this American novelty bike?

  35. Hey! It’s me again.. I rebuilt the forks and they are much better… But I’ve ran into another problem… The thing won’t idle down!! I cleaned the carb really well but no difference. I cleaned the petcock, fuel filter etc… My air filter is clean, and my throttle cable isn’t sticking. While the engine is racing and won’t idle down I sprayed carb cleaner on the intake boot and nothing changed. I was driving it in first gear, (about 15 mins after I first started it) and it all of a sudden started racing and wouldn’t idle down… I killed it and then it backfired… It’s a 1981 SR250… Please help.. Thanks!

  36. New gas, and yes the cable is. Now it’s not starving/racing after I cleaned the petcock again. But I ran into another problem… It’s kinda sluggish in first gear.. at lower rpm’s if you give it WOT it kinda bogs down. It hesitates.. But it only does it in first though. And the hesitation only lasts a couple of seconds.. But when you get on it hard when its not moving it definitely feels like it has a power loss. The air/fuel screw is adjusted right too. Any ideas? I can live with it, but i’m a perfectionist so it gets annoying. Thanks for all your help!

      1. I don’t think so.. I don’t remembered if I told you before, but it has a power loss too. Maybe I should take the carb off and soak it in gas. I dunno… It’s becoming a pain.

  37. hi I’ve bought new brake shoes for front wheel the pad wont allow for a good fit do i need to file it down some they are the exactly the same as the old ones only with more pad., so it is a supertight fit which does not allow for expanding.

    1. You may have to file the pads down a bit.

      This is fairly common with older bikes as the drums wear over time, which can distort the shape slightly (the wear makes the drums oval in shape).

      But, check the brake cable has been slackened off before you try to fit the new pads (the cable should have been tightened as the old pads wore down and is likely to be adjusted too much for the new pads to fit).

  38. got it to fit and I now have front brake working again… ok, my 82 sr250 has only speedo with indicator lights no fuel gauge and no tachometer. I have been wondering if it is possible to install a tachometer I installed new speedo which looks so much better than the original but would like to have a tachometer to add to its looks can it be done?

    1. I’m fairly certain the SR250 had a speedo and tacho as standard (at least the UK one’s did?). I think the rev counter ran off a cable that went into the top of the engine.

      There wasn’t a fuel gauge on the SR250, basically, make sure it’s not on reserve and flip the fuel tap to ‘reserve’ if it starts to run out (then when you fill up remember to put the fuel tap back to normal).

  39. thanks it seems mine is an american version which lacks the tacho. ill just have to find one for looks only. by the way is there any way to drop pics on this blog?

    1. I installed an aftermarket electronic tach when I rebuilt and modded my SR250. It is not too difficult, just need to solder in a couple wires. Hardest part was finding which wire was which, needed to use my multimeter.

  40. Hi from South Africa. I bought a SR 250 engine to fit into a quad bike. It was quite a job but it’s in and if the engine would just start, it’ll be a success. It seems the Hitachi TID11 – 02 Ignition unit is faulty and I have not succeeded in finding one locally. My question: can I replace it with an other make/model? Any other suggestions from anyone?

  41. Hi, I have a 1986 Sr 250 which, over the last couple of trouble free years, has earned my utmost respect. However it has recently developed an annoying popping and banging from the exhaust on the over run which is accompanied by a tinny rattling sound from thee area of the exhaust down tube. I have examined the exhaust and it seems entact and hole free. The inlet manifold looks a little suspect, but it has since owning the bike. Any ideas anyone.

  42. Hey everyone! I am the proud owner of an 81′ SR250. I checked the oil around 2-4 months ago (I can’t remember for sure). I just checked it after a 15 minute ride, parked it on a level floor, put it on the center stand, and to my surprise in the window on the engine, it was only half way full. I’m not sure if this is good or bad? Should I add more? Thanks! Merry Christmas everybody!

    1. Yes, I would advise keeping the oil topped up to the maximum, especially if it’s leaking oil.
      It’s not uncommon for older bikes to use a bit of oil. Have you seen any excessive smoke from the exhaust or can you smell burnt oil when riding?

  43. No, I haven’t. But sometimes as soon as I start it up when it’s pretty cold outside, I do see a little black smoke come out when I give it some throttle but it smells like exhaust. And I only notice this when it’s cold. I’m not sure if it’s just exhaust or if it is burning oil. Thanks for replying! If it is burning oil, what would you have to do to fix that? Or is it important enough to fix?

    1. Usually it would mean replacing the piston rings &/or possibly a cylinder re-bore (as the rings wear, the gap between the ring and the cylinder wall get’s too big and oil is able to get past the ring into the cylinder, where it’s burnt with the fuel).
      What’s the mileage on the bike?

    1. Unless the engine has been seized or damaged at some point it’s unlikely to be engine wear with only 5000 miles on it? Do you notice any oil patches underneath it in the morning (if your not sure, park it on a clean patch of ground and put some white paper underneath, this should show any oil leaks).

      1. Yeah I haven’t seen any oil patches. Well I think I’ll just leave her as is, and if I notice any problems take it to the shop. Thanks man! Merry Christmas!

  44. hi, I’ve just finished rebuilding the top end, new O/S piston and rings, rebored cylinder, new/used cylinder head, new valves , new/used camshaft, new rocker arms. This because the camshaft and rocker arms were beyond repair and led to exhaust valve damage which then damaged piston and riding on freeway about 60mph it just exploded, why it happened was explained to me by an honest engineer whom I met not so long ago. I have put it all together and while waiting on the parts I stripped it all wiring and chrome parts to clean and paint frame, now I have engine rebuild complete and am hooking up the electric but it seems that in the diagram provided in the yamaha manual it does not match the colours I have on the bike. Are there other wiring diagrams for the 82 sr250 and where may I find them?

      1. All of the wire connections are correct and match colours, the lead wire however does not match with what it connects to. Perhaps there was some change made. I have it operating and am thrilled that I was able to rebuild her and clean out case and now ride her again. What tyres can be used on these rims? And what aftermarket rear shocks can you recommend?

  45. Just wondering what other front forks can be put on an 81 sr250 without having to change anything? finding it hard to find roadworthy shocks so trying to find something else

    1. The Yamaha part number for the original, complete fork was: 3Y6-23100-00 (discontinued now though!). Looks like the complete fork was only used in the early eighties SR250’s.
      However, you could possibly fit most other forks that had the same stanchion diameter (32mm) as your SR250, but if your using one from a different bike it would be best to buy a complete front end with the wheel, brake etc?

  46. I just got a 1982 model from a shop that I do alot of business with,with no papers! It needs a head gasket and I’m sure a few other things! I’m going to take off the turn signals and tail-lite and remove the speedo cable…then put knobby tires on it and handlebars more suited to off road use and have a decent little trail machine for newbies to the sport…also,it’s what my kids will be learning to use a clutch on later this year! eBay actually has some parts and you can always use TT & XT 250 parts from similar year models too!

  47. Good evening from Washington DC. I was hoping you would know where I can buy a new petcock. Went on Amazon, but not sure it will fit the bike. Thanks for your help.

      1. I’m hoping is foes fit. It looks the same. My problem is it won’t arrive till May 10th, then if it doesn’t fit I have find another solution. By the way I have a 1981 SR250, which I converted to a bobber.

  48. This a brilliant site by the way. I’ve had a 1980 SR 250 for 4 years now and use it every day to get to the station. I try to keep it in good nick. 2 years ago I had to replace the silencer. I chose one from a catalogue and it works fine but it’s too small and consequently makes one hell of a din. Can you recommend a replacement that would suit? As soon as I bought it I realised the neg pressure fuel tap wasn’t working. I’ve replaced with a conventional on off fuel tap. I did try to order a replacement but it didn’t fit under the lip of the tank. Again, have you got any recommendations?

  49. Hi I have a 1980 sr250 that I just got running again and im not to good at mechanical work for it yet so I was hoping you could tell me why it is bogging down when I try to pick up speed, I think its the carborator but im not sure yet, your advice would be much appreciated

  50. im trying to figure out how to set the timing. i am a novice mechanic at best and this is my first bike. any and all info is appreciated.

  51. Hello again, Could you help me with three things (1980 SR 250 SE) 1. Can you possibly recommend an silencer? I replaced the old one using a catalogue and it was a bit small. I’ve had it a couple of years and want to replace it. 2. Also what would be the best rack for a top box? 3. (As per previously posted) I had to replace the original neg pressure fuel tap with a new on/off fuel tap (the mechanics threw it away). The delivery isn’t great – certainly not smooth. Could the fuel tap effect the carbs performance? I’ve had the carbs adjusted and looked at but the delivery is all a bit rough. Never needs choke from a cold start. Often cuts out when idling – always have to use the throttle to stop this. Every so often a small backfiring. Any ideas would be very much appreciated. Is the fuel original fuel tap for the 400 the same as the 250?


  52. Is there anyone on here that can tell me the difference besides the obvious engine displacement, between the SR185 and the SR250? I have the 1981 SR185 and can find little to nothing on compatible parts.
    I would love to know if the front fender is interchangeable. I think the chrome looks really good and the SR185 has plastic.

  53. I have had a sr250g I bought new in 1980 it has been a great bike I rode it from Illinois to Arkansas and from I’ll to Houston tex the two longest rides it was newer then and I was younger I found it will run 85 that pegs the speedo on mine so probably a little faster. It now has 35000 miles on it and has a little oil spot on left side but runs fine. Right off the bat in fact the day I got it I changed the handle bars to some dirt bike bars and took the seat off and cut out the hump that hits your tailbone. I have replaced tires once and chain and sprokets twice. If you lug it it will throw the chain off and once it bunched up and cracked the outer cover on front sprocket (I have seen this on another sr250g) it is the only motorcycle I have bought new zero miles and the least trouble of any I have had. I didn’t get carb worked on till last year a friend talked me into running sea foam through it said it would clean it out it did then I took carb to a shop and had it cleaned right. A great little bike I don’t think anything off the 185 will work on it. Also when I bought it I got a Yamaha service manual an if you look on eBay you might find one a lot better than haynes or others in my option. The only thing mine really needs is new shocks and seals in forks but I still ride it a thousand miles a year. Also a few years ago a friend gave me one just like it missing the tank and seat but a lot of good parts. I am glad other people enjoy these as much as I do. Dennis

  54. I have an 82 SR 250 Exciter, it has a clunking noise from the trans in first gear only. Was wondering if anyone else had hat happen, haven’t torn into to look at yet.

  55. I never had that with the sr250 but in 1959 I had a Harley hummer that made a clucking sound and it finally locked up it had a tooth off of a gear.

  56. Hi from Philadelphia.
    I just picked up a 1980 SR250 yesterday. My first motorcycle, and I’m super psyched about it. It runs great and I plan to ride it until the weather gets too cold then spend the winter disassembling, cleaning, and modding it. I intentionally bought this bike because I want to learn, and these seem to be fairly simple as far as road bikes go.

    I have a couple questions off the bat if anyone is able to answer…

    1. Manuals for this seem to be hard to find. WhiteDog, the links you’ve posted to Amazon are no longer in stock. I see some on ebay that say “owner’s manual”. Maybe a dumb question, but is this the same as “service manual” that I see others referring to in this discussion?

    2. The bike is electric start only, as most know, but there is a plugged hole in the engine that says “kick starter”. Has anyone had experience and success at installing a kickstarter? Any tips on finding the right part(s) for that would be appreciated.

    Thanks in advance!

    1. An owners manual is normally a basic summary of info about the vehicle (what the lights, switches etc do, basic service stuff etc). A service manual normally lists a break down of every job on the bike including specs, tightening torques etc.

    2. I was thinking of trying that installation this winter. I like the idea of having a backup to the electric, esp with such a small engine. Bike store said I could get parts to do it for about $109. But I’m dubious as to whether that will include all necessary stuff. Will let you know.

  57. Hi, I’ve got a sr250 1981 plate. When it needed a new chain abd sprocket set my mechanic suggested upgrading from standard 45/16 to 40/14. He said it should give me a touch more top end speed. However – not the case! It now pucks up fine through to 4th gear but no matter what the revs when i chande into 5th gear it drops and won’t go above 6k revs and looses speed too, drops from about 70 down to 60mph. Mechanic said I want getting revs high enough before changing up but even at full throttle no difference. Has anyone any ideas why this is happening? Thanks for any advice

    1. That’s a big change in sprocket sizes for such a small engine, you might want to try a smaller change first and see how you get on.
      You could try using a standard rear sprocket and a 15 tooth sprocket on the front to start (or the standard rear and your 14 tooth front to see if it improves)…….

  58. how do i check the oil levels on my 1980 250 cc yamaha solo. is their only engine oil or is there gearbox oil as well. please help. thanks

    1. There’s either a small window for checking the oil on the side of the engine (leave it to settle for a few mins and make sure it’s sitting on level ground before you check it though) or there will be a dip stick attached to the oil filler cap (which you would see if you unscrewed the cap).
      Can’t remember which one it is as it’s been a looong time since I changed the oil on one of these.

      The gearbox and engine use the same oil, so you only need to fill the engine with oil. You should need about 1.6 litres of oil if your changing the oil and filter.

      Hope this helps πŸ™‚

  59. Happy new year! I would like to know if the 1982 sr250 can use a kickstarter from another model. I want to install akickstarter and lose the battery. It is not a popular bike here in the U.S. and finding the kickstarter for it appears impossible.

  60. Thanks to everyone for posting on the yamaha Exciter 250….i just recently bought a 1980 model one myself in amazing condition and only 2,700 miles on it….my only real question involves upkeep….what are some simple easy ways to ensure this little bike keeps going strong after all these years of non-use?oh and does anyone know the weight limit for it?with a passenger?

  61. Hey guys. Juat got my girlfriend a 1984 SR 250. Was sitting for years apparently, carby all blocked up.. today i stripped that and got the carby cleaned up, had an issue with the float and the carby flooding.. fixed that now..
    But now its running like crap, 99% sure its running way rich.. my question for you guys is, where the bloody hell is the mixture adjustments??? Am i missing something obvious?
    All i can find is one brass screw under the throttle cable?? Help a guy out haha cheers.

  62. Hey man, I’m sure you remember me (you’ve helped me out a lot in the past). Hope you’re doing well πŸ™‚ I’ve got some running problems with my SR250 (1981), and I’m hoping a carb rebuild will fix it. I’m getting most of the parts OEM from Yamahapartshouse, but they don’t carry the pilot jet anymore. I have everything I need in my cart except the pilot jet, lol. Was wondering if you knew of one for it? If so please send me a link. Part # is: . Jet, Pilot #47

    Also, what is the difference between SR250TH and SR250H? Thanks!

    1. Seems to be a few people selling jets in the US (link below):

      SR250 carb jets on Ebay…

      Not too sure on the exact differences between the H and TH models, I think 1 model might have been a more ‘cruiser’ style bike (slightly different bars etc) and 1 might have been the more basic, commuter model.

      But, I can only seem to find references to the H and TH models in some parts catalogues, which are well known for making mistakes with the model codes (i.e. there not always a reliable source of info)! πŸ™‚

  63. Hey man. So I have almost got the carb rebuilt, (waiting on one more jet, should be here tomorrow). It’s running way better, but still rich. We’ll see if the new pilot jet fixes that, it may or may not. I know it needs a new one anyway. But my question is, are you supposed to adjust the pilot jet, or main jet? Really noob question I know. Nowhere in my manual does it say about adjusting anything in the carb except the float height. I’ve read some things online, and haven’t found much info. When putting my carb back together I usually just tighten the jets down. Thanks, have a great weekend

  64. And also just to let you know, this carb does have a air/fuel screw. Would be on the engine side of the carb, usually a black cap kinda thing over it with a little tiny hole. To do any adjustment to it you have to get it out, by either drilling it out, or getting a screw to go in it and pulling it out.

  65. Been working on an 1982 for my wife (it’s an heirloom from here mother) and it’s time for a new rear tire. I’ve done a bunch of mods to give it a Thruxton look and would like to figure out the widest rear tire she can run as I find that helps cornering on my Bonneville. Any idea what rear max rubber width would be?

  66. I’m loving this blog and thankful for this info. I just bought my first bike last week. One question, I’ve bought an aftermarket speedometer by acewell. I can’t find a speedo sensor cable that fits my 1980 Yamaha sr250. Any suggestions? Thanks!

      1. I think I have found the right cable. My next issue is that the bracket which holds clutch to the handle bar cracked while tightening. Do you know where I can get one?

  67. Hi! I have owned several SR250s now and often refer to this page for info – thanks! Now I can perhaps contribute something back…

    I am doing a series of tests to establish a baseline for engine operating temperature – cylinder head temp and oil temp. You can see everything in this thread here: http://www.dotheton.com/forum/index.php?topic=70174.new#lastPost

    But perhaps most relevant to this page is the readings I found for oil pressure! You can add them to the page if you like?

    From cold 90C
    Idle: <0.5psi (pretty much unregistered on gauge)
    On road: 0.5-1.5psi

    Thanks again for the useful page!

  68. Hi I’ve got an SR250SE, 1981. When I got her she struggled to do 55mph, engine work and a new exhaust later got it up to 65mph, 70mph on the flat. My mechanic suggested changing the sprockets front and rear)would give me a bit more top end but it’s actually made things much worse. I have very little power in 5th gear, she gets up to 70mph in 4th gear but when I change up to 5th the revs drop right down to 5.5k and speed drops to 55/60 mph. Also engine gets hot. The mechanic insists I must be changing up too soon but it’s full throttle before I change. Pull off and lower speeds are fine so it’s not a problem around town but I can’t keep up on the A roads at all.
    Really annoyed I spent good money to make the bike worse! Any advice please?

    1. You’d probably be better off running the standard sprockets for now.
      If it’s struggling with revs you might want to check that all the filters are clean (especially the air filter), check there’s no cracks, leaks or blockages on the fuel and air pipes (especially check the carb to engine rubber for cracking), if this fails you might want to check and clean the carb….

  69. My Dad has a 1981 SR250 he bought brand new in 1981. I used to ride it and often and it never exceeded 68mph. That is on a flat stretch of freeway several miles long. He still has it today and has it up for sale. It has about 1200 miles all original still looks brand new. Anyone around the Flint MI area. Interested?

      1. Front brake switch is located next to the front brake lever and the rear brake switch will be above the back brake pedal (there should be a spring coming off it, if you follow the spring you’ll find the switch).

  70. I’m on the SR-train now! Just bought a 1980 SR250 yesterday, in pretty rough shape to be honest.

    It had sat for a decade, but by the grace of god, wasn’t seized and started right up with some starter fluid. I plan on removing the tank and carb, cleaning and rebuilding each, and replacing the fuel lines to get it running off of regular gas. After that, the full rebuild will commence!

    Had a question about the front forks though – has anyone considered a disc brake change? I want to drive this around town here in East Tennessee, and the thought of drum brakes on the steep hills doesn’t resonate very well with me. Has anyone replaced the front forks to accommodate a disc setup? Any experiences would help greatly!

    Looking forward to being an active part of this forum!

    1. Here in Spain there are quite a forum, where owners say they has change to disc and they not have found much improvement .
      Also you would have to change all the front fork and bottel of suspension too
      Good luck

  71. Hi from Spain
    After completed dissasembling the engine of my Sr250 Especial had problem with the gear change as could not get further than second gear.
    I open up again and found that I had put the two inside forks in the wrong order (they are not identical)
    Put them back in what I thougth the right way and now can`t get to 4th and 5th gear.
    Any ideas????
    After opening the beast three times I may be able to help with any question.

  72. Have a 81 sr250. Bobed it out, fun as hell. Notice the bottom of the exhaust is rusted out. Can I add any exhaust that fits? The part rusted out is the bottom attached to the frame.

  73. Advice – I Have just come in possession of a 1994 Yamaha SR250. It runs well etc however is not original which doesnt bother me as a I plan to turn this into a 60s style scrambler/Enduro. I believe they are stock wheels front tyre 90/90 H18 and Rear 130-90-16-67H, I want to put on some Trail/Road tyres to improve the look (obviously not the handling) however im struggling to find a set that will sit on the stock wheels. Firstly does anyone know what tyres would fit, secondly is it pretty much the same stock set up as the XT250?

  74. I have a 1981 SR250 TH that I’ve owned for about 22 years now. Excellent shape but just don’t ride it much anymore. Would like to see it go to a good home. Anyone interested? It’s in the NE WI area.

  75. What tire options does a guy have for a pair of dual purpose tires for the 18” front and 16” rear that are a close tread match!?
    Hard to find here in Canada eh

  76. I just got a USA 1981 Yamaha SR 250 with only 3200 miles at Cycle Salvage in Redding CA for only $250. It has the pizza box on the back. Cheers.

  77. Hi Guys,

    My SR250 has was repaired with the carb from a different bike. The specs for the cars on this page are:
    Carb type: 34mm Mikuni carburetor (carb parts)
    Carb type: BS34-III
    Pilot screw opening: 2 turns
    Float height level: 3mm (+ or – 1mm)

    I cannot find a BS34 anywhere for this bike. Can I use a Mikuni VM34-168, VM-34275, or VM34-389? or a TM34? I can find all these parts online, but I am not knowledgeable enough to know which will or will not work for this bike. I would really appreciate some guidance .


  78. Hello, I just bought an 81 yamaha sr250 exciter and I live in the states I played $250 for it and it doesn’t run yet and the owners before me cut 40% of th tail pipe off and just welded the end of it to the pipe about where my center stand is should I just leave it for now or replace it completely

  79. I have a 81 Sr 250 with electric start the bottom end was trashed .so I had a 80 something xt250 motor laying around and they look identical except for one mounting hole at the drop tube and it is a kick start also the wires are different and there’s a few extra wires I hooked up all the wires of the same color to the corisponding colors to the sr250 harness and I get no spark also I noticed there’s a compression release on the bottom end I swapped on from the xt250 itseems very hard to kick over did I screw up will this set up not work with out the xt heads I put the good head and jug on from my sr250 on it ? And is there any way I can find out what colors of wires are for what I haven’t been able to find a decent diagram that I can read or be able to see the script is too little and goes blurry when I try to zoom in
    Any help would be awesome I can take pics and send them of what I’m dealing with if it helps thank you !!! Scott

  80. Any free service manual for this bike and how to troubleshoot clutch lever push rod thats connected to the clutch cable…. on the face of the clutch basket cover where does the air does an arrow on the face of the clutch plate cover where does it point to how to align it how do I troubleshoot my cleats from my clutch plates not moving back and also how do I fix my

  81. I’ve just bought an 81 250 which has been completely overhauled and looks mint. Only done 1700 original miles as it was I a barn for 35 year. Anyway, haven’t ridden it for a couple of weeks (occasional Sunday spinner as I have. Trophy for every day) and when I turned key on there as no neutral light. Checked all wires and nothing. Finally married it down to the relay bolt inside the engine case. Cleaned it as it was grubby, took small screw out and shorted wire to outside of bolt. Neutral light came on fine. Decided that’s the fault so proceeded to remove bolt. On the last thread it FLEW out, followed by a good gallon or so of petrol. I turned the tap off but it kept coming. Looks like there was already all that petrol in there. How did it happen, how can I fix it? Any ideas as I’m not sure of how this bike operates yet

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