Service & Parts

Technical & Tips

Service Manuals

Factory Service Manual

Honestly you simply have to get one of these, there is nothing quite like a proper Kawasaki manual. Note that there are 11 different versions of the manual –  as later bikes were released the manual was updated with supplements.  It does detail the technical differences so make sure the manual you have covers your bike.  This online PDF is up to 1990 and is a free download but you will need a DropBox account (also free).

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Generally considered a good compliment to the official Kawasaki Service Manual. Specifies it covers UK bikes 1984 to 1996, US bikes 1983 to 1986. Free online link.

These are also other covers of the Haynes manual, I’m assuming they are earlier releases.  On the back cover or inside the front they generally list the models and specific years, always worth checking.

I suspect this Ninja manual only covers the GPz from 1984-86.

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Note it only covers bikes 1984 to 1986, I don’t have this so can’t comment on it’s value. Other members have said it has more detail than the Haynes but there are some worrying errors with torque settings. Haven’t found a free copy online, this link is to shop and you can also find this (and others) on eBay etc.

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First port of call for Parts

GPZ Zone

The GPZ Zone (Craig) is one of the best online resources for any new or replacement part for any GPZ bike.  They also run their own online forum for UK Owners, there is a nominal £5 annual fee for membership.

Feb 2021 

Normally they ship world-wide but with a 3rd Covid lockdown there are significant delays and international shipping is currently suspended until further notice.  I believe the Owners club is not taking new membership and will close in 2022.

click here for website

The GPz900R Shop
Sean.J is an expert on the bike and can supply a huge range of secondhand parts all over the world from the UK. There is also a FaceBook Marketplace page.

click here for eBay shop

Kawasaki Schematics & Parts Databases

Surprisingly it is quite difficult to find definitive online resources. Some sites clearly identify the A5A, so European sites that don’t aren’t listed here!  A1& A2 bikes were obviously sold in Europe and Australia, yet nearly ALL online resources only show US schematics for these bikes. MSP is the only link for European bikes earlier than 1986 – even the official Kawasaki Europe site only starts at 86.

Real Estate-wise on a 1366 pixel wide laptop (yup old school….) I find Megazip gives the best balance of detail and information and CMS allows you to zoom in on the schematic for the best clarity of individual parts.


Ross. B picked these up in 1990 so it ‘strongly’ suggests that there are schematics for Aussie bikes right back to the A1. I think the +A3 info is available online, not 100% sure of the A1 & A2 (see Aussie schematics below).  Unfortunately scanning these isn’t simple….

I suspect that there were microfiche developed for different markets, the most likely being US, Europe and possibly Australia.  A quick review of online auction sites shows that these microfiche had many different Kawasaki part numbers, dates and releases.

It is also curious that Kawasaki define the A2A & A2B as distinct variations.  Apart from the A5A no other versions have any variation – even on the microfiche for these later models. 

I have not seen the A2A & A2B variations listed anywhere else, not have I locate anyone (yet) who knows what they refer to.  They obviously can’t be significantly different to the stock A2, however it highlights that even after almost 40 years there is still gaps in GPz900R reference information.

It would be be useful to have a full collection of these digitised for reference, I have set up a GoFundMe campaign for just this purpose.

Model Year Part Number Date Release*
A1/A2/A2A/A2B ’84~’85 9917-1171-05 Aug 85 (E)
A3 ’86 9917-1171-02 Nov 85 (B)
A3/A4 ’86~’87 99918-1033-03 Sep 86 (C)
A3/A4/A5/A5A ’86~’88 9917-1171-06 Mar 88 (F)
A10 ’93 99918-1093-01 Oct 92 (A)

*guessing at Release, although this seems redundant as the files already have a date.  And with an (A) starting in Oct I doubt that these are related to dates at all.

Impex Japan - (1984-2003 All except Oz)

An online parts supplier based in the Japan.  The most comprehensive online resource I have found because it includes all years, including 3rd gen bikes, and quickly identifies bikes from different locations – except Australia of course.

The schematic diagrams aren’t the largest and can’t be zoomed which makes it hard to view on mobile devices – on the computer it’s fine.  and although there is no dynamic schematic function The information is extremely comprehensive and shows superceded part numbers and their current replacement – brilliant.

Curiously I have never been able to get the site to translate consistently to English, for me it continually coverts to Russian!


You would expect this to be a definitive online catalogue, however it only lists the ‘Ninja’ from 1984 to 1986. So I’m  pretty sure this only represents the US-built bikes built/assembled in Lincoln Nebraska.  You won’t find a GPz900R here!

Technically it is a good resource if you have these versions, however no dynamic mouse functions and the zoom/pan buttons for schematics is pretty clunky.  But you can download comprehensive pdf files including schematics and all of the matching part numbers – really nice feature.


MSP (Motorcycle Spare Parts) - (1985-1990 & 1993 UK/Europe)

This is the *only* one online resource I have found (so far) that lists non-US bikes earlier than 1986, although strange that it doesn’t list 1991.  The format is excellent and although the schematics aren’t resizable the parts lists displays shows a photo of the actual part in many cases. Nice touch.

What is interesting is the 1985 schematics not only also show the US-schematic change in crankcase, pistons, head & cam cover but include frame numbers as well as the engine numbers for engines ZX900AE & ZX900AG.  Of course US schematic engine numbers only match with ZX900AE engine series.

As the frame number references go right back to 001 this suggests these schematics apply to A1 bikes as well.

So why does this site have US data, after all not even the official Kawasaki Europe site has these.  And there is a notable difference to the US ones I have found, these schematics ALSO show a transmission change for the bikes that is NOT shown in any US schematics.  What does this mean? No idea except nothing is ever simple!

It has a really nice feature where you have an image flyout when you roll your mouse over the schematic index.  These images can be quite small and the titles aren’t always the same from version to version.  For example the starter clutch isn’t always listed here!




Kawasaki (EU) - (1986-1991 & 1993)

You would expect the official Kawasaki Europe site to be the comprehensive online catalogue, however like many others it only lists bikes from 1986 to 1993.  I understand that the bikes were not sold in Europe post 1993 but no idea why there are no listings for the A1 or A2.

The site offers a direct VIN entry.  But… doesn’t work for my Australian A8 even though this VIN decodes properly on other European IV Decoder sites.  So grain of salt here I think.

It does list the A10 & the A5A as both Firecracker Red OR Ebony and is one of the few sites to identify a UK version.  I note although the Ebony link returns parts diagrams (common for all A5) it does not return any specific part numbers, unlike the Firecracker Red option – so perhaps there is a connection between the A5A and different colours..

Schematics do have a dynamic mouse function, however I suggest using a different highlighting colour to GREEN would make it a little more obvious!



CMS (Consolidated Motor Spares) - (1986-1988, 1990 & 1993 Europe & UK)

An interesting online parts supplier based in the Netherlands specialising in parts for UK & European delivered bikes for just these listed years. 

Although the schematic zoom layout is a little quirky, you can open a large image.  It also shows the photos of many parts (brilliant) and uniquely offers the direct microfiche list scans of parts.  These are two very useful features so if your bike is one of these (especially UK owners) it’s a great resource.



Megazip - (1986-1993 & 1998-2003) EU/JPN/MLY

An online parts supplier *similar* to Impex, no idea why it doesn’t include some years. 

Select the year of your GPz and it provides the factory part diagrams, just click the part you need in the diagram to immediately get a price and a Kawasaki Part Number. As per Impex schematic diagrams aren’t huge and can’t be zoomed.

FYI showing the change in starter clutch design from 1992.

CLICK TO OPEN LINK IN NEW TAB - (1986-1990 & 1993 EU/UK)

Another European online parts supplier.  Nice setup as when you select a year it shows you visually the different regional markets (eg. UK) as well as the different color schemes available in each market.

At the intro page the schematics index has a flyout which makes locating parts much easier, the schematics have a dynamic mouse feature and are presented in a portrait layout.  Again a useful site if your version is listed.



A pre-requisite was that these links have a local Australian phone number to call AND have PN for the CVK32 airbox & rubbers – unique to Australia and not shown on international databases!

I noticed that OZ schematics showed PN for the Ebony/Gray A8. I’ve never seen one here, so asked on FB and Richard.L had a picture of one he owned in NZ. However Terry.C said that there were completely different Oz & NZ distributors (thus were completely different bikes) and in Australia we only got the Ebony/Red A8.

So as always there can be conflicting information on these bikes!

Matt Jones Motorcycles - (1986-1991)

May 2021 Update: this is the most complete online reference I have sourced so far (however not used).

As per other sites choose your Year first and it will present a GPz900R in the list of motorcycles to choose from.

A nicely formatted site with the ability to open (and download) a larger schematic (~800×1000) however no dynamic mouse linking.  All parts seem to get a price, however when you try to Ádd to Cart’ or click directly on anything unobtanium the site reports that you need to get in touch first.

Another benefit of this database (compared to the others) it not only shows the current part number but any superceded ones as well.  This is really useful for our local bikes to correctly identify things that have changed over time or might be different to European bikes – eg mirrors.



Elliot Brothers of Bendigo - (1986-1991)

May 2021 Update: during analysis of paint colours I discovered that these schematics (also used by Coastal) are strangely missing some (not all) PN for the ebony/gray A8.  By cross-checking PN I have identified another local reference ( that has this missing information.  Obscure but still a data inconsistency.

However these folks have been used and suggested by Mark.N.  From the Kawasaki page (link below) you select a year from 86 to 91 and a link to the GPz for that year will show up.  A nice format with zoomable schematics and dynamically linked mouse, so as you roll over the schematics it highlights the part in the schematic and the details list.


Coastal Motorcycles - (1986-1991)

May 2021 Update: during analysis of paint colours I discovered that these schematics (also used by Coastal) are strangely missing some (not all) PN for the ebony/gray A8.  By cross-checking PN I have identified another local reference ( that has this missing information.  Obscure but still a data inconsistency.

Another site that looks like it uses the same data as Elliot Brothers.  From the Kawasaki page (link below) you select a year from 86 to 91 and a link to the GPz for that year will show up.  A nice format with zoomable schematics and dynamically linked mouse, so as you roll over the schematics it highlights the part in the schematic and the details list.

A minor site glitch is searching by Part Number.  If you use the top level [SEARCH BOX] it works fine or from the Part Finder link there is another [SEARCH BOX] that also works fine. The glitch is when you are in the Schematics pages there is a third [SEARCH BOX] that doesn’t work at all, despite the PN clearly being in this models parts lists.  Just something to watch out for.


Note: There must be a question as to whether this is the US (Lincoln) bike data, as the versions only match US production, there is no data for any other models, and the bike is referred to as ‘Ninja’.  

Note you have to search for ‘ZX900’, as ‘GPz900R’ returns no match!  A decent site, if you roll your mouse over the schematic it will show you the details for that part.  As mentioned this schenmatic is showing covers as US, Ca or Cn only, the emissions port head was ONLY used in the US (unti +2000 in Japan/Malaysia!)

Again this suggests that the data is for US bikes, and although a lot of parts would be the same there were many minor differences (eg. pegs).  Unfortunately without a definitive Aussie A1/A2 reference the validity of this schematic for Aussie bikes is unconfirmed.


GPz900R Online Parts 

The suppliers offer replacement parts for your bike.

Amazing selection (Feb 2021 over 2,400) of new GPz900R parts from Japan. Not cheap.

World's End motorcycles (UK & Oz)

Nice selection of new GPz900R parts that can filtered by the version of your bike.  Have an Aussie version site, may hove other versions based on your location. (Denmark)

A Danish company that has a really nice selection of new GPz900R parts including brake rotors, flashers, gaskets, etc. (Japan)

Yep we all know about eBay and here’s a Japanese equivalent that often has lots of amazing and affordable GPz900R parts from Japan.  Pretty confusing as there are lots of different shipping & processing fees that apply. (Japan)

Miraculously I purchased a NIB deep contour (drops me by 40mm) seat for my GPz900r off Gumtree.  The box shows it was from Japan, and working backwards brought me to this website.  They have an online shop (Google translates pretty well and I have contacted them by email to see if they ship internationally.


The original bike came with twin-pipe system finished in black chrome with were two muffler lengths – long (Europe) & short (US, Australia maybe others).  Both made of unobtanium.  Decent second-hand sets are sometimes available and they will cost you roughly the same as a new set, maybe even more.   Many aftermarket 4-1 or 4-2-1 exhausts (like those on webike.japan) all seem to be fitted to bikes without the front or belly fairings.


Unfortunately research suggests that commercial chrome re-plating companies avoid used mufflers because of the carbon contamination they create in the plating tanks.  It may be possible to re-chrome or ceramic coat new systems before installation.

Sito Mufflers

A forum member suggested these Sito cans as a good replacement, they are black chromed.  I think Sito is a brand name manufactured by the Italian company  but I can’t see anything on their site that matches these. This link is to where they list the part number as #1275.  Sito are also available from several sellers on Ebay but the part number is #1276 and listed as suitable for the GPz1100 – I don’t know if it fits the GPz900R.





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Manufactured in Italy and generally considered to be the closest match to the original twin systems.

However there has been some discussion on the quality of the black paint finish – sometimes inaccurately described as ‘chrome’.  Some members have reported it degrades very quickly and they would have preferred to get the system supplied as raw steel and finish it themselves.  Whether this is possible I do not know.

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These are manufactured in Germany, and I have emailed them in Feb 2021 and they have replied (so NOT physically confirmed) that they fit under the OEM fairings of the bike.

Hi Adrian, Yes all of them confirmed.

Mit freundlichen Grüßen / Best regards

Auri Huesmann


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When browsing through eBay this listing caught my eye as a very similar system to what is currently on my bike – of which I have no idea.

I emailed the japanese seller mukeidou who promptly replied that they built the system directly onto a GPz. They sent the following photos showing it installed onto the bike, and although this GPz isn’t stock I specifically asked it the system fit under the standard fairings.  They have replied that they do, of course this is NOT physically confirmed.

Hello again,

Yes, the exhaust pipes can be installed together with the OEM full fairings.
Thank you so much for your consideration.

Best Regards,

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Interesting Parts

Aftermarket Carbs

An expert GPz member (Gosling1 from the ksr-au forum) reckons one of the simplest performance upgrades to the engine is simply flat-side carbs and different cams, though I would need convincing regarding the cams unless you are racing.  But of course you can use modified profile camshafts (nothing new here) and here’s some off-the-shelf parts or these guys will mod yours – there would be local suppliers in your region I suspect.

Carbs seems like a really easily mod if you can afford it, all owners who have made this upgrade appreciate the more responsive throttle you get with flat-slides vs CV carbs. And whilst these are kinda pricey (Apr 2021 AU$1,500) if you paying someone else to rebuilding your existing carbs then by the time you add up parts & labour it’s probably  closer than you might think.

Mar 2021 This seller has a set of refurbished carbs for AU$1200…..

Click here for a YouTube video on how to rebuild your carbs.  One supplier claims up to 25% more power (yeah right) but even if there were small (10%) improvements, especially if this could be tuned for to improve low or mid-range running, it’s probably worth considering.


RS36 or RS40*

I added the asterisk because although the RS40 is listed as being suited for the GPz900R it’s also listed as being suited for the GPz1000RX or even the FJ1200. I’m pondering if the Ninja would even have the airflow to match the CFM of these carbs without other modifications.

Mar 2021 update.  FB GPz900R Owners member Chris. R races his bikes, highly recommends flat sides (properly set up on dyno) and suggests  Keihin FCR 37 for stock and only FCR39 for racing (modified motor). 🙂

My only issue with the Keihins is at $AU2,707 hey are almost TWICE the cost of Mikunis!

Apr 2021 update.  Another forum member makes the point that the heavier springs used inside a flat slide carb makes for a much heavier throttle, fine for racing but makes for hard life on the road.

Racing swing arm

A swing arms to suit VERY wide wheels and tyres with options for 3 diffrent types of swing-arm stabiliser.  Fancy.

This is another design, impressive but unavailable.

Other folks have used ZX10 or ZX636 swing arms, the japanese custom builders look they prefer to use use these fancy modern designs.

Aftermarket Rims

Carbon fibre, I’m not joking.  Wow – 2.9kgs fo the rear?  Wow again.  Well they need to be red for my A8, and I might as well get the ceramic bearings.  Only £2,755.83……not counting shipping from the UK to Australia!

Or for about the same cost you can get magnesium OZ Racing rims from Japan.


This is a photo of a magnesium Dynamag which IMHO looks more original.


Sean J. also recently (Apr 2021) found a set of 16/16 Mavic rims that came off an A1, however given the unusual sizes these were probably for a GPz1000RX.  If available in A8 sizes the design would match quite well MHO.

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Springs & shocks

This is an Aussie site with decent pricing, excellently descriptions and huge range – front & rear –  to suit the bike no matter which version you have.  Longer shocks (+5mm, harder shocks (for 17″ rims) the range of options for the bike is amazing, and that alone suggest they are worth a look.

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CNC pick-up cover

A member of Kawasaki GPz900r Owners Manfred.W can supply you with a windowed cover for 149€ plus postage.  Get in touch through FB!

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Stunt bars (90-93)

I’ve seen a few bikes where the owners have done this handlebar mod themselves.  Her’s an off-the-shelf option.

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The original bikes have slightly different set-ups. US bikes, with their higher handlebars, moved the pegs forward and down for a more upright riding position. From schematics I think 3rd gen bikes (+A12) also had slightly different positions.  As they were part of the superbike race scene there were plenty of after-market bits available however they ae getting quite difficult to source new.

This is another option from Japan.

However I’m confused by the ‘aggressive peg position’ being just 20mm back & 30mm up from standard?  That can’t be right?  On my A8 that is no-where near enough to really make any significant difference.

Anyway I’ll admit it would be nice to adjust the pegs back for spirited riding – however my riding observation that the greatest benefit comes when you are tucked down behind the wind shield. I don’t need them raised, but about 100mm further back would be a nice balance and more knee-friendly.

Kawasaki refers to these parts as as Muffler Stay (LH & RH) and they are found in the Battery Case schematic diagram!

You can actually  ride using the rear pillion pegs and although you look like a land-speed record racer (& a bit of a wa**ker!) they really are just that little bit to far back to be practical, annoyingly they easily fold back up (lol!)  & obviously your feet are nowhere near the brake nor clutch.

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Streetfighter yoke (83-89)

Again an off-the-shelf part for those after the street bike bar conversion.

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Fairing bolt kit

I’ve seen some kits from China and others charging 2-3x as much for a stainless steel kit.  This is a very fair price IMHO and look waaay better than the hardware store bolts that I use. Grin.

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Paint Colours
I have read that Kawaskai doesn’t keep colour codes for older bikes – great!  Anyway Firecracker 606 is apparently the red from the 82 and 83 models.  This is a recipe provided on an online forum.

Dupont Chromapremier Base/Clear Coat
16 oz.

886 J Opaque Red 65.5
864 J Magenta 93.0
850 J Brilliant Red 118.6
853 J Red Orange 140.0
807 J LS Black 141.5
62320 F Binder 308.1
62330 F Balancer 438.7

Another Aussie forum user has used spray-can brake caliper paint for rims. Cheap as, strong durable paint and looks pretty darn close!

However the link here is to where they let you select you version and they give you back the colours and how to order.


A1-A6 OEM-look Brake Rotors

Being manufactured from unobtanium here is an Aussie company still offering original design rotors. The GPz900r Shop also has listed on his FB page some custom manufacturers parts that have that OEM look.

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Replacement screw and bolt Kit
This eBay seller list two stainless steel allen head bolt kits for the Keihin carbs and the engine

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Ignition Components

In Apr 2021 the price of a OEM replacement CDI black box on eBay, landed in Australia, ranges from AU$90 from legend Sean J. to over AU$400.  Coils are also not cheap secondhand (~$73), and there is a good argument to replace with ‘new’ units like Dynacoils.

Australian supplied kit price Apr 2021 AU$259

I have the 2.2Ω coils (can also use 3Ω) Dynacoils and they work great, but they are basically newer versions of old tech.  The new Dynacoil systems use Microcoils and along with the rest of the setup has some pretty amazing features.

  • position switch with 4 ignition mapping options
  • adjustable rev limiter
  • can act as a password protected ignition interlock
  • PC programmable

Having built track car engines I know this is pretty fancy tech for a very reasonable price (Apr 2021) of AU825 not including shipping.  Especially when you consider just the aftermarket CDI box will cost around AU $500.  Add this to new coils and the complete kit is just not that much more.

Aussie supplier link

Cheaper Options

Without an ‘old-school’ distributor you can’t manually advance the overall ignition timing on the GPz900R, so one solution is to replace the standard ignition plate.  Many owners have done this mod and recommend it, but it’s not universally accepted that it’s an improvement.

These aftermarket parts sometimes turn up on eBay and advance the overall ignition another 4°.

However if you could do this electronically inside the CDI unit this seems a much more elegant solution AND it’s easily reversible.

Feb 2020 Update: during a recent discussion a variant of this CDI (GPZ250R CDI [21119-1172])  was suggested because it raises the rev limit.  I contacted the supplier who did not recommend this and that they can reset the rev limit anyway.  It also emerged that the CDI from the GPX600R works on the bike (along with some peculiar others), and it was thought that this includes additional electronic spark advance.

However from the ZX600 Haynes Manual specifications (non-California model) you only get a 2.5°change at (32.5° vs 35°) 1@10,000rpm and the ignition is identical (10° BTDC) at lower rpm – plus it prefers the higher resistance (3Ω) coils. 

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JIS Screwdrivers

I’ve read that the bike uses Japanese Industrial Screws (JIS) instead of the standard Phillips head.  I’ve also read of folks stripping carburetor screws because of the softer materials used and the slight difference with the JIS profiles.    I haven’t actually got a set of these but if you were servicing fasteners inside rotating components or doing a carb rebuild a set of these is probably a sensible idea.

You can obviously get these from anywhere, and there really isn’t any sense in buying cheap versions.  This is a local Aussie supplier I have bought stuff from before (crimping kit) – good quality and value.

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6 Pot Brakes

Yup, you can even upgrade the standard 4-pot brakes on your A7-A10 to the 6-pot versions used on the later Japanese bikes.  Not sure they will stop you better nor convinced that adding more un-sprung weight is a good idea – but they look fancy!  As per the eBay listing I think these will become rarer and rarer.

Note that these are not interchangeable with the single piston brakes used on the original A1-A6 front end.

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Silicone hoses

Whilst silicone is generally something we mention whilst eating garlic, brandishing crosses and muttering prayers of any religious denomination (ie not something you want in your engine!) there is an argument to use silicone hoses over rubber and given that OEM hoses are expensive maybe it’s a more economic option to use aftermarket.

Schematics show that apart from the top radiator hose nearly everything is straight, so I wondered if you could simply buy a roll of hose like this for AU$75 – which when you consider is for 3m makes it an absolute bargain compared to buying short pieces from your local motor parts store!

The short lower hose from Kawasaki is AU$20, so this got me wondering about the economics silicone kits. My local Kawasaki dealer had them at around AU$250.  Scalding…. However there are online suppliers who offer kits for the bike, however none of the ones I have found includes the top radiator hose. So then I was wondering I maybe a kit from another bike had hoses that could be trimmed to suit.

Another complexity/cost is some folks reckon you need quality hose-clamps with silicone, t-bolt design the best.  However these are always more expensive than worm-type and have less range.

Kits I have found are shown below with  as of Apr 2021.

Ram Air: $60 but all suppliers out of stock.  Thermostat to radiator hose looks a little simple compared to other kits.

AS3 Performance: $76 but not including shipping. Also kit appears to be missing a short hose!

SAMCO: $223 from an OZ supplier (lots of other international sellers) and note kit does include clamps.

Dura-bolt: $214 from webike not including shipping

Big One: $80 from but doesn’t ship to Australia. Of course.


Mar 2021 Update

Another group member reported excellent results with a length of silicone hose, the slight ‘set’ actually works really well as most OEM hoses have a slight kink anyway.


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Kwick-fix alternator/starter chain tensioner

This is one of the options to fix clunking during starting, a common age-related problem with many Kawasaki’s of this era. This site gives a good run-down of the problem as well as how this product fixes it. There other options discussed on the Technical – alternator chain tensioner page of the site.

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Engine Guard Temperature Sensor

This is a really affordable (AU$99) temperature sensor kit that can even work as a low oil pressure alarm.  Sensors are as simple to install as adding a washer. Aussie company as well!

Phillip from Engine Guard (whose brother owns two GPz900R’s!) recommended adding an LED as he thought it unlikely you would ever hear the warning buzzer when riding. And I reckon he would be right!

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Matris Cartridge Forks (1999-2003)

In Mar 2021 I got myself a GoPro Session and was testing in different locations.  This spot gives a great view of the front forks in action and they work really well, especially on this scenic ride, so it made me wonder why many folks upgrade.

The consensus from other owners was that the 2nd gen forks are a common upgrade to 1st gen bikes.  The limitation of the system is really only dealing with mid-corner bumps at speed, the damping just isn’t able to keep up (see short video below).  All in all there really *isn’t* any reason to upgrade for road use, most owners do it simply to tinker.

However when doing a bit more online research I found these cartridge forks by Matris and a local UK suppler  Bike Torque Racing .  Note I haven’t included them as a distinct parts supplier because although you can get braided lines and chain/sprocket sets (prices look very reasonable) there really doesn’t seem to be much else – and you don’t actually get to this fork set if you search for GPz900R!

By cross-checking the *very* limited online information regarding +A12 bikes from the schematics it does look like the forks are slightly different to the +A7.  I’ve contacted the supplier to see if they know anymore – the complexity is that +A10 bikes were only ever sold in Japan (for 1 year) and the rest were only for Malaysia.  They certainly weren’t made in the volumes of US/European bikes and In the online groups I’m in no-one has one of these bikes.

Update: Jake from Bike Torque Racing replied very promptly – unfortunately they don”t have any other info except that it is specifically listed for +A12 biker – so he doubts it would fit earlier forks.  Fair enough.

A8 A10-11 A12

For me this would be one of the mods I would consider *if* they fitted my A8 forks. But although they look similar AND  use the same handlebars AND top yoke how the heck would the preload adjusters fit?

I would not consider drilling a hole in the handlebar component as being a wise engineering decision…

If you had to buy these AND a +A12 front end it would simply be waaaay to expensive.

The image link is to an eBay seller which give you a comparitive price.

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Chinese Radiator

This is a link to a chinese aluminium radiator.

Currently selling on eBay for just $138 (Apr 2021) including delivery (from Melbourne supposedly) this compares to about $1000 for a replacement radiator from webike.

The detailed discussion on the install of this radiator is here.

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Pingel Petcock

The OEM petcock isn’t considered great, however A8 bikes have a different tank and a different petcock part number. Note that there is only an a newer common petcock from Kawasaki.  It is absolutely NOT RECOMMENDED to be a cheapskate with this part – a leaking tap can hydro-lock your bike.

Many owners recommend US company Pingel, I haven’t found an Australian supplier.  This is to a UK store that actually only lists the GPz750, however it is reported to be the right one including the required backing plate.  There are many different orientations available, I’ll try and get a owner installed image.

Apr 2021 price look quite reasonable at around AU$160 from eBay (US) when you consider the direct replacement from the GPzone is AU$150.

GPzone replacement – not shipping internationally (Apr 2021)

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Unobtanium Parts

Lockhart Fairing

A fibre-glass replacement middle fairing that was reported to improve cooling, not entirely convinced it improves styling!

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Muzzy Fan

At one time available as a direct replacement for the plastic OEM fan, with rigid AL blades the cooling efficiency should be better and the blades can’t melt!  There are online second-hand sites that claim to have Muzzy blades that fit, but they did appear to be quite model specific. I haven’t found an active link to a HT-H5A, the image is from an old online auction.

This is a pretty definitive list I sourced from a japanese parts page.

HT-H16 1994-1998 Ducati 916 Aluminum fan blade
HT-H7 1987-1990 CBR-600 F Hurricane aluminum
fan blade
HT-H7 1991-1994 CBR-600 F2 aluminum fan blade
HT-H7 1995-1998 CBR-600 F3 aluminum fan blade
HT-H6 1986-1987 VFR-700 F/F2 Interceptor aluminum
fan blade
HT-H6 1986 VFR-750 aluminum fan blade
HT-H6 1990-1995 VFR-750 aluminum fan blade
HT-H6 1993-1999 CBR-900 RR aluminum fan blade
HT-H6 1993-1996 CBR-1000 F Hurricane aluminum
fan blade
HT-H1 1986-1987 ZL-6 A Eliminator aluminum
fan blade
HT-H1 1985-1997 ZX-6 C Ninja aluminum fan blade
HT-H2 1990-1993 ZX-6 D Aluminum fan blade
HT-H2 1993-2003 ZX-6 E Aluminum fan blade
HT-H2A 1998-2002 ZX-6 R Aluminum fan blade
HT-H3 1995-1997 ZX-6 R Aluminum fan blade
HT-H1 1987-2003 KL/KLR-650 aluminum fan blade
HT-H5 1985 Vulcan 700 A1 LTD aluminum fan blade
HT-H5 1987-1990 Ninja 750 aluminum fan blade
HT-H5 1986-2001 Vulcan 750 aluminum fan blade
HT-H4 1990 ZX-7 Aluminum fan blade
HT-H3 1991-2003 ZX-7, 7 R/RR Aluminum fan blade
HT-H5 1995-2000 VN800 aluminum fan blade
HT-H9 1996-2002 Vulcan 800 Classic Aluminum
fan blade
HT-H9 2000-2002 Vulcan 800 Drifter Aluminum
fan blade
HT-H9 2000-2002 Vulcan 800 A Aluminum fan blade
HT-H5A GPZ900R / Ninja 900 全年式
HT-H5 1985-1986 ZL-900 A1/A2 Eliminator aluminum
fan blade
HT-H3 1994-2003 ZX-9 R Aluminum fan blade
HT-H4 1986-1987 Ninja 1000 Aluminum fan blade
HT-H4 1988-1990 ZX-10 Aluminum fan blade
HT-H4 1995-1997 GPZ-1100 Aluminum fan blade
HT-H5A 1999-2000 ZRX-1100 aluminum fan blade
HT-H4 1990-2001 ZX-11 Aluminum fan blade
HT-H5A 2001-2003 ZRX-1200 aluminum fan blade
HT-H12 2000-2001 ZX-12R Aluminum fan blade
HT-H5 2002-2003 ZX-12 R aluminum fan blade
– (2個必要となります)
HT-H8 All models Kawasaki 1300 (except KZ1300)
Aluminum fan blade
HT-H3 1992-1993 GSXR-600 Aluminum fan blade
HT-H2A 1996-2000 GSXR-600 Aluminum fan blade
HT-H3 1994-1996 RF-600 R Aluminum fan blade
HT-H2B 2000-2002 GSXR-750 Aluminum fan blade
HT-H2 1996-1999 GSXR-750 Aluminum fan blade
HT-H3 1993-1995 GSXR-750 Aluminum fan blade
HT-H3 1994-1996 RF-900 R Aluminum fan blade
0008-00002 2001-2002 GSXR-1000 Aluminum fan blade
HT-H3 1993-1998 GSXR-1100 Aluminum fan blade
HT-H13 1999-2003 GSXR-1300 Hayabusa aluminum
fan blade
0008-00001 1997-2001 Triumph Daytona aluminum fan
0008-00001 1999-2002 Triumph Speed triple aluminum
fan blade
0008-00001 1999-2002 Triumph Sprint aluminum fan
HT-H7 1999-2002 YZF-600 R6 aluminum fan blade
HT-H17 2001-2003 FZ-1 1000 Fazer aluminum fan
HT-H9 1989-1996 FZR-1000 Aluminum fan blade
HT-H10 1999-2001 YZF-1000 R1 Aluminum fan blade
0008-00003 2002-2003 YZF-1000 R1 Aluminum fan blade
HT-H5 V-MAX 全年式
HT-H5 1986-1993 XVZ-1300 Venture/Royale aluminum
fan blade

Graham B. noted his metal fan blade, purchased of eBay some time ago, was manufactured by Master-bilt and stamped ‘Brookside’

The blade does fit perfectly and he reports it moves a lot more air.  However Master-bilt is a refridgeration supplier and the only link I came up with for ‘Brookside’ is a different 5-bladed/4-mounting hole design.  It may be that they still have the fan that fits, the challenge will be to find it.

Many 8″ steel exhaust fans are available on eBay, it’s a question of whether the weight of steel is too high for the OEM motor and, of course, no idea if it actually fit,

The diameter of the OEM cowling is 200mm (8″) which is standard,  however to give clearanve in the curved housing the fan is 170mm (6.7″) which I would suggest is VERY non-standard!


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The OEM windshield is polycarbonate.  One of the negatives of the blazing sunshine we have in Australia is degradation of any clear plastics, no matter what material they yellow over time.  For my A8 screen this can be mostly polished out (annually), the technique is exactly the same used to clean up our yellowing plastic car headlights!  Almost any good polish works with decent elbow grease, Google ‘toothpaste’ for the really cheap solution!

However my issue goes deeper than this, literally.

The polycarb has internal ‘çrazing’ that means fine micro-cracks in the material that significantly reduces clarity under some light conditions & direction.  Rare but it’s there.  I would love to replace the screen but although there are many aftermarket companies (including several in Oz) offering many alternatives(tinted, race versions) they all use acrylic.

I do use my screen when riding.  If our old backs let us tuck down behind it it works surprisingly well when it’s cold & raining and is especially beneficial when crossing paths with a double-b semi-trailer.  Which also have a nasty habit of chucking up rocks.  Although I do admit my scariest moment was actua llywith a very low-flying parrot, I really did flinch expecting contact.

I realise it’s completely personal choice but I’m not a fan of acrylic winshields (why none are listed here) and I have not found a polycarb alternative.  

Superceded Parts

It looks like the original screen was replaced, at least for 2nd gen bikes.

  Windshield Trim Windshield Trim Cowling LH Inner Cowling RH Inner Cowling
A1 39154-1051 53044-1119 53044-1120 55028-1066 55028-1067
A8 39154-1091 53044-1119 50344-1229 55028-1066 55028-1067

*US schematics for 84-86 list 39154-1091



Voltage Regulator

Kawasaki PN: 21066-1056 or Nippon Denso RTRG25.

A common part for Kawasaki, Suzuki, Triumph & Yamaha alternators of the time, not really unobtanium but based on prices must include plenty of platinum.  These are seriously expensive, I’ve seen online prices well over +AU$400, and as of May 2021 they are about $AU280 landed from UK eBay sellers.  In comparison Sean J. sells a complete second-hand alternator for ~£60 (AU$107).

May 2021 from OEM OZ Kawasaki parts

May 2021 from after-market supplier – US Dollars as well….

This is an much cheaper after-market solution, still available but does seem to be getting harder to find.  A YouTube link on how to install this is here.

May 2021 ~€82 (AU$127)

FYI theis link is to an Aussie dealer that gives excellent details on the OEM part, you would need to enquire about the price.

Component Repair/Replace Info

Alternator AU$165

If the alternator goes you can replace or rebuild.

Replace with another

When purchasing a second-hand unit you can check that the plug is still attached to the lead BUT due to the buried plug location it is impossible to simply replace the alternator. I ended up buying one without the plug and just spliced it in.  I recall it being quite fiddly to align everything up and get it back into place – as usual patience and perseverance are the key traits.

Sep 2020: was quoted AU$165 for a second-hand unit from a local wrecker. I don’t recall my unit being that much, IMHO those numbers are probably spent rebuilding the old one.

Replace with ZRX

Apparently some US owners have used the ZRX1100 or 1200 units, obviously the same basic engine was used on later bikes (GPz1000RX) and it seems likely that the component was also shared.  Probably work double-checking part numbers.  At the end of the day newer is always better.


Here is some technical info from for those considering rebuilding:

This Kawasaki model uses a Nippon-Denso car-type alternator that is mounted behind the cylinder block. Inside this alternator there is a field rotor with copper slip rings on which carbon brushes run. Around the rotor you will find the stator and in the front of the housing are the built in rectifier bridge and the electronic voltage regulator.

Common faults:

FAULT 1: OVERCHARGING THE BATTERY.  This is usually caused by (1) a bad internal voltage regulator or (2) a bad electrical connection somewhere on the bike in the lead that provides battery voltage feedback to the internal voltage regulator (the voltage sensing wire) The replacement voltage regulator is our part# ESR025. This unit replaces the OEM unit even though it looks different. To find the bad connection to the voltage sensing wire you need to look at the leads coming from the alternator. There is one large diameter lead, usually RED, that is the output from the alternator to the battery. The thinner lead is the sensing wire for the regulator. Use a multimeter to measure the voltage on this lead to ground. It should be close to the battery voltage with the bike running (around 14Vdc). If you see a substantial difference (say: battery voltage 17Vdc, sensing lead 14Vdc)you should look for a bad connection somewhere between the battery and this sensing lead. Inspect all connections, the ignition switch, use spray contact cleaner on everything. Spend some time and you will probably find a bad connection somewhere. Fixing this connection should fix your overcharging issue.

FAULT 2: NO OR LOW BATTERY CHARGING. This can be caused by a bad internal voltage regulator inside the alternator, or by a bad rectifier module. A bad voltage regulator sometimes is caused by a shorted out field rotor that is drawing too much current from the voltage regulator. Inspect the rotor resistance between the slip rings which should be 3.3-4.0 Ohms. Another cause could be bad connections between the alternator output and the battery terminals. Check all connections and see if this fixes the issue.

Brush Set

Here is a link to a replacement alternator brush set.


Here is a link to a video on replacing the old rectifier

Front fork service AU$330
You can do this yourself but you need plenty of workbench space AND releasing the internal nut can be difficult, especially without the factory service tool. The square-taper factory tool is available in a couple of variants (57001-183 & 57001-1057) – which you can use for all versions of the bike.  Only cost around $50 which is reasonable.

However you can also use filed broom handle or ground bolt, etc. as long as the measurement across the flats is 22mm for 1st gen bikes. 2nd gen bikes had bigger forks so apparently the measurement is 27mm.  One of the best solutions is to use a tube spanner – apparently the OEM plug spanner is a perfect fit.  Recently a forum member bought a 7£ set of tube spanners off Amazon and because they can be nested worked perfectly!


You used to be able to get just one fork serviced, but recently it seems like the only option is to service both at the same time.

Which makes sense, and $AU330 is very reasonable compared to the effort of doing it yourself.

However I was surprised to get the bike back with the original badly cracked dust seals – I understood that that all seals would be replaced. It makes absolutely no sense to me to not replace these when the entire forks are dis-assembled.

I recalled previously asking another Kawasaki service centre who assured me that all seals would be replaced, however I was told that new service kits do not always contain the dust seals. Hmm…..OK. So something to check IMHO!

Anyway my local Kawasaki service centre was very reasonable and put in new dust seals for no extra charge. Greatly appreciated.

Water pump seal kit £33.60
The GPZ900r engine doesn’t normally drop any fluids, so coolant on the ground was a clear sign of a problem.

Note the GP Zone website describes leaking oil, I’m 90% sure mine was leaking coolant. Either way purchasing the seal kit directly from GP Zone makes this a relatively painless repair, I see you can even buy a rebuilt waterpump (£199) if you simply wanted to plug another in.

GPz900R (ZX900) Database

Number of owner contacted & confirmed bikes.


















Top Gun

About the Site

My family loves older vehicles, the newest one we own is 2003!  But I am acutely aware of the ownership complexities especially:

  1. they often need more 'hands-on' mechanical work &;
  2. there often isn't any local expertise from the service centres;
  3. there is often no new parts available from the manufacturer;
  4. parts often have to be sourced 2nd-hand or from overseas.

So we often end up doing a lot of the research & work ourselves and this information gets stored either locally with the bike or online forums - although finding the useful parts in these forums isn't always simple.

The original goal of the site was simply somewhere for me to record service work & contacts on my GPz900r so that my kids (the one that likes bikes anyway!) could easily access it - it doesn't concern me if it was publicly available.

I then realised that with this online structure in place I could also offer it to other owners, and the site could potentially expand to record other owners experiences and expertise , meaning we can learn from others but also pass on this knowledge to subsequent owners of these wonderful motorcycles.

At least Covid-19 has given me plenty of spare time to pursue my passion for the motorcycle!


South Australia



1983 - Honda XR200
1984 - wanted a GPz
1985-2013 - cars+family
2014 - finally got one!


The information provided on this site (or links) is personal experiences from non-professional home-mechanics, so neither it's accuracy nor it's validity can be confirmed.  If you need professional advise please visit your local Kawasaki dealership or a qualified industry professional.

Like riding any motorcycle, at the end of the day the only opinion that really counts is your own!

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