Kawasaki ZXR400 H (1989 to 1990) Specs

Note: A Trochoid oil pump has an inner and outer rotor with different numbers of teeth (e.g. the outer rotor can have 5 teeth and the inner can have 4 teeth). The difference in teeth creates uneven spaces inside the pump which causes the oil to move to fill the gaps as the inner rotor rotates (example below, not from a Kawasaki engine).

Unfortunately, these pumps do suffer from pitting if the incorrect oil has been used in the engine (e.g. car oil).

Note: You can use any grade oil in the ZXR400 engine (mineral, semi synthetic or full synthetic). Although fully synthetic is the best and will offer the best protection for your engine, we normally recommend a semi synth as it’s a good balance between engine protection and price. More info…

Note: You’ll need a clutch holding tool (EBC part: CT004) for removing it, a clutch lever if you’ve dropped it and possibly a clutch cable if it’s suddenly stopped working!

Why is the chain free play important? The free play allows the chain to remain tight enough to drive the bike as the swing arm moves (the swing arm movement increases/decreases the chain tightness).
If the chain is too loose it’s likely to skip over or off the sprockets and if too tight the chain can snap and trash the engine casing.

Why is throttle twist grip and choke cable free play important? Because the throttle and choke are mounted on the handle bars, they move as the handle bars move and this movement causes the cables to loosen or tighten.
If the cables are too tight, this can cause the throttle or choke to operate when the bars are turned, if they are too loose they may not work.
The free play allows the throttle or choke to only work when the rider wants them to (as opposed to operating when the bars are turned).
The free play should be checked with the handle bars in the central (straight ahead) position.

Sintered brake pads are made using heat and pressure to fuse metal particles in the pads together which makes them very resistant to friction (friction causes the brakes to overheat which leads to brake fade in extreem cases). This gives better braking but they can be alot noisier then normal pads.

Due to their design, upside down forks are much stronger then conventional telescopic forks which means they improve a bikes handling. The only downsides of upside down forks is increased stanchion and seal wear due to these parts being in the area most affected by road dirt and debris.

Note: As a very general rule of thumb, most upside down style forks use a 5w (light weight) fork oil and most conventional forks (with the stanchion at the top) use a 10w (medium weight) fork oil.
As stated, this is a GENERAL rule so always double check with your local dealer if your unsure.

Note: The low seat height made the ZXR400 popular with ladies and shorter riders.

Note: Wheelbase is the measurement between the bikes front and rear wheels (usually from the center point of the wheels), length is the total distance between the outermost points of the front and rear of the whole bike.

What does a regulator/rectifier do? A regulator/rectifier (or reg/rec for short) has 2 jobs. The rectifier converts the AC (alternating current) electric from the alternator into DC (direct current) electric so that it can charge the battery. The regulator makes sure the voltage is kept within certain limits so not to damage the battery and other parts.

Note:

• The YB12A-A battery is a 12 volt, 12 amp/hour battery and is length: 134mm width: 80mm height: 160mm in size (more info…).
• The 1st letter(s) of the battery reference code is a manufacturers reference mark and may vary between different battery makes (different battery manufacturers use different 1st letters), so CB12A-A, YB12A-A and DB12A-A are all the same battery just from different manufacturers (more info…).
• Also…… Avoid buying the cheapest of the cheap type batteries online as they have a horrendous failure rate (and they can be a bug!er to post back when it fails).
• This is a conventional battery, which means it will need topping up with distilled water occasionally.
  For those that don’t fancy doing that, there are many maintenance free and gel equivalent batteries now available.

What does a CDI do? CDI stands for capacitor discharge ignition (or ignitor, but it does have many other names as well). Basically, CDI’s store energy which they use to tell engine parts like spark plugs, coils etc when to fire.
Because they store the electricity, this makes them much faster then conventional, mechanical parts and they don’t often need maintenance (as they don’t have any moving parts). Most bikes built after 1980 will probably have some form of CDI. More info…

Note: Although all the ZXR400 H CDI’s we have had have the part number ‘21119-1271’ on them, we have been told that the CDI’s with the part numbers ‘21119-1299’ and ‘21119-1270’ fit (these may have been from bikes that were imported from other countries, but as we’ve never tried fitting them please check against your old part before buying!)

Note: If possible, it’s always better to buy new coils for your bike. Unfortunately, although many breakers (like us!) test coils prior to putting them up for sale, because they are used, theres no knowing how long they will last, buying new coils, although often more expensive, is usually a safer option.

Note: All servicing mileages and times are APPROX! (as I couldn’t seem to find an accurate list of H model service schedules…)

You can use mineral and fully synthetic engine oils in the ZXR400. We don’t normally recommend mineral oils as they offer the lowest levels of protection for the engine (so if you are using a mineral oil make sure you change it often!). Good fully synthetic oils (from well recognised brands like Shell, Silkolene, Rock Oil, Castrol etc) are fine for use in the ZXR400, and they offer the highest levels of protection for the moving parts, but, the cost can be prohibitive (you get what you pay for, good oil ain’t cheap baby! :-p ). More info about different oil types can be found HERE.

Note: Fork seals normally have the size as a set of 3 numbers (e.g for the ZXR400 H1 the fork seal size is 41x53x8). The 1st number is the internal diameter of the seal (41 for the ZXR400 H1, the edge that goes against the fork tube, this will be the same diameter as the fork), the 2nd is the external diameter of the seal (53mm for the ZXR400 H1) and the 3rd number is the thickness of the seal (8mm for the ZXR400 H1).