GPZ400 ?

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bluespear
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GPZ400 ?

Post by bluespear » Fri Sep 10, 2010 3:47 pm

Hi

Does anyone here know anything about GPZ400's ??

Are there any / many parts interchangeable with ZZR's ??

TIA

Gary

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Re: GPZ400 ?

Post by sh4d0w0lf » Sun Sep 19, 2010 1:38 pm

Hi, i dont know much about the GPZ400's but i beleive that parts are interchangeable with the GPZ600's and some parts with the GPX600's i.e. i believe the engine from either 600 will bolt straight in but will need electricts to suit ect... the fork from the gpz6 will probs bolt straight in ( i think they are the same frames...!)

Hope that helps somewhat.

Adam.

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Re: GPZ400 ?

Post by thunderace » Sun Sep 19, 2010 8:52 pm

It all depends on which variant of the GPZ400 you get, there are two. The 400R is an IL4 and the 400S is a parallel twin. The 400R returned 59BHP and the 400S 54BHP.

Most 'service' items on the GPZ550 and GPZ600 will fit the 400R but I never found much to fit the 400S. Luckily, Kawasaki seem to have a good parts stock of 400 import items at hand here in the UK. I found anything they didn't have could be obtained straight from Japan within 7 days. IIRC, brake pads are the same across these four models excepting the rear - the 400S has a drum where the others have a disc.

You won't be able to fit 550 or 600 forks as they are 37mm and the 400R and 400S have 42mm forks.

The frames are also different between the 400R and 550/600 (the 400 frame is shorter) although the engine from either will fit the 400R but you will need the full loom, coils, CDI, etc from the donor bike. You will need to use the 400 carbs, re-jetted to suit, and air box (both are physically smaller than the 550/600 equivalent), also use the 400R carb rubbers as they are shorter in height. The 400S frame, being a twin is obviously not going to accept an IL4 lump.

Both run 16" rims with a 100/90H16 front and 130/90H16 rear. I used Pirelli Sport Demons on both my GPZs and they were superbly suited to the bike and my riding style. The very earliest 400Rs (also known as the ZX400) did run 18" rims front and rear in 100/90H18 and 110/90H18 format but they were changed to 16" in 1986.

The only major worry to be aware of is collector box rot. Replacements are even more rare than NC24 ones. The 400S O/E system was a 2-2 system with balancer pipe at the bottom of the headers under the engine, just in front of the centre stand (yes, a centre stand! the 400R didn't have one). The 400R has a 4-2-1 system as standard. The most popular (and I think the only off-the-shelf) system is the MOTAD stainless, 2-1 for the 400S and 4-1 for the 400R. You can fit the MOTAD silencer on either side in the case of the 400S, you just fit the headers and collector on the opposite way round.

The only other potential issue is the indicator electrics. On both my bikes I had to re-wire and replace the whole indicator circuit. These issues were caused by water ingress around various fairing joints but careful re-routing of cables and joints solved this.

Of the two bikes, I would buy another 400S if I could find one. Mine, which I owned from the day it landed in the UK, had a very rare engine churning out 74BHP. According to the paperwork that came with it the engine was a highly tuned version made by Kawasaki amid talks of a 400cc race series in Japan in the early-mid 80s, of which only a handful were actually fitted into bikes. It is one of only two bikes that I wish I had never sold, the other being my 1998 R1.


As far as parts being swappable with the ZZR400, I would imagine that most parts can be swapped onto the 400R. IIRC, the engines are the same basic block but with different carbs and CDI.

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Re: GPZ400 ?

Post by sh4d0w0lf » Tue Sep 21, 2010 11:14 am

If it helps i have a 600R that im thinking about selling for spares / repairs as its in bits atm...

msg me if ure interested.

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Re: GPZ400 ?

Post by bluespear » Tue Sep 21, 2010 10:37 pm

Many thanks guys for your input - every little helps (as they say).

thunderace wrote:It all depends on which variant of the GPZ400 you get, there are two. The 400R is an IL4 and the 400S is a parallel twin. The 400R returned 59BHP and the 400S 54BHP.

Most 'service' items on the GPZ550 and GPZ600 will fit the 400R but I never found much to fit the 400S. Luckily, Kawasaki seem to have a good parts stock of 400 import items at hand here in the UK. I found anything they didn't have could be obtained straight from Japan within 7 days. IIRC, brake pads are the same across these four models excepting the rear - the 400S has a drum where the others have a disc.

You won't be able to fit 550 or 600 forks as they are 37mm and the 400R and 400S have 42mm forks.

The frames are also different between the 400R and 550/600 (the 400 frame is shorter) although the engine from either will fit the 400R but you will need the full loom, coils, CDI, etc from the donor bike. You will need to use the 400 carbs, re-jetted to suit, and air box (both are physically smaller than the 550/600 equivalent), also use the 400R carb rubbers as they are shorter in height. The 400S frame, being a twin is obviously not going to accept an IL4 lump.

Both run 16" rims with a 100/90H16 front and 130/90H16 rear. I used Pirelli Sport Demons on both my GPZs and they were superbly suited to the bike and my riding style. The very earliest 400Rs (also known as the ZX400) did run 18" rims front and rear in 100/90H18 and 110/90H18 format but they were changed to 16" in 1986.

The only major worry to be aware of is collector box rot. Replacements are even more rare than NC24 ones. The 400S O/E system was a 2-2 system with balancer pipe at the bottom of the headers under the engine, just in front of the centre stand (yes, a centre stand! the 400R didn't have one). The 400R has a 4-2-1 system as standard. The most popular (and I think the only off-the-shelf) system is the MOTAD stainless, 2-1 for the 400S and 4-1 for the 400R. You can fit the MOTAD silencer on either side in the case of the 400S, you just fit the headers and collector on the opposite way round.

The only other potential issue is the indicator electrics. On both my bikes I had to re-wire and replace the whole indicator circuit. These issues were caused by water ingress around various fairing joints but careful re-routing of cables and joints solved this.

Of the two bikes, I would buy another 400S if I could find one. Mine, which I owned from the day it landed in the UK, had a very rare engine churning out 74BHP. According to the paperwork that came with it the engine was a highly tuned version made by Kawasaki amid talks of a 400cc race series in Japan in the early-mid 80s, of which only a handful were actually fitted into bikes. It is one of only two bikes that I wish I had never sold, the other being my 1998 R1.


As far as parts being swappable with the ZZR400, I would imagine that most parts can be swapped onto the 400R. IIRC, the engines are the same basic block but with different carbs and CDI.

While I am sure you know much more about these than me, I have an observation or 2:
Mine is a GPZ400r - IL4, says so on log book & on Kwak stickers on the bike. It does have a centre stand (optional extra?) as well as side stand. Its got a Nexus 4-1 exhaust on, but also has an exhaust mounting on the left side rr peg hanger. ???

It was a difficult to start & didn't tick over well - but I think thats because the rubber trumpets (between airbox & carbs) weren't actually connected properly at the carb ends - they've gone oval & hard & were gaffer taped to the carb inlets. Also the crank breather pipe wasn't connected to the bottom of the airbox.

The electrics all seem to be ok except that the hazard light switch sticks (hazard lights on a 1986 bike - who would have thought it ?!?!?)

I know that Kwaks have a reputation for being a bit rattly, but mine seems to have a bit of a knock at very low revs (below 2000 ish) rev it more and its not too bad ...... problem or not ????

Also, if I hold the revs up & then release the throttle it take about 5 or 6 seconds to return to idle. The cables and exterior carb mechanisms all seem to move freely, so is that an internal carb problem or the bad airbox seal ???

TIA for any input,

Gary

BTW here's a link to some pics, will post more soon :

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... geName=STR...

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Re: GPZ400 ?

Post by thunderace » Wed Sep 22, 2010 7:41 am

bluespear wrote: While I am sure you know much more about these than me, I have an observation or 2:
Mine is a GPZ400r - IL4, says so on log book & on Kwak stickers on the bike. It does have a centre stand (optional extra?) as well as side stand. Its got a Nexus 4-1 exhaust on, but also has an exhaust mounting on the left side rr peg hanger. ???

The centre stand may well have been an optional extra, mine wasn't fitted with one. I believe there may have been a run of 400Rs fitted with a 4-1-2 system, either that or mine had a rare 4-1 fitted from new.

It was a difficult to start & didn't tick over well - but I think thats because the rubber trumpets (between airbox & carbs) weren't actually connected properly at the carb ends - they've gone oval & hard & were gaffer taped to the carb inlets. Also the crank breather pipe wasn't connected to the bottom of the airbox.

The carb rubbers are the same as the 550/600. These will fit http://cgi.ebay.co.uk/Kawasaki-GPZ600-G ... a3ff5c9558 not cheap though at £30 a set.

The electrics all seem to be ok except that the hazard light switch sticks (hazard lights on a 1986 bike - who would have thought it ?!?!?)

Both of mine did exactly the same after a while. I stripped the switchgear down and gave it a good clean with contact cleaner. Worked fine afterwards.

I know that Kwaks have a reputation for being a bit rattly, but mine seems to have a bit of a knock at very low revs (below 2000 ish) rev it more and its not too bad ...... problem or not ????

I had this too with my 400R. For the life of me I never found out what it was. The only thing I could think of was slightly low oil pressure at tick over causing a lack of oil flow around the crank. It never really caused me any problems and the current owner hasn't any either.

One thing I would recommend checking is the cam chain. Check it is still tight and there are no dinks out of the links (turn the engine by hand with the rocker cover off and plugs out).


Also, if I hold the revs up & then release the throttle it take about 5 or 6 seconds to return to idle. The cables and exterior carb mechanisms all seem to move freely, so is that an internal carb problem or the bad airbox seal ???

This could be caused by the airbox seal or it could be sticky carb floats/needles. It would be well worth giving the carbs a good clean if you haven't already.

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Re: GPZ400 ?

Post by bluespear » Wed Sep 22, 2010 8:30 pm

thunderace wrote:
bluespear wrote:

It was a difficult to start & didn't tick over well - but I think thats because the rubber trumpets (between airbox & carbs) weren't actually connected properly at the carb ends - they've gone oval & hard & were gaffer taped to the carb inlets. Also the crank breather pipe wasn't connected to the bottom of the airbox.

The carb rubbers are the same as the 550/600. These will fit http://cgi.ebay.co.uk/Kawasaki-GPZ600-G ... a3ff5c9558 not cheap though at £30 a set.

No mate, not those. I meant the trumpet shaped plastic/rubber things in the end of the airbox, which attach to the carb inlets & are held in place by long, tightly coiled spring things. My carb rubbers are fine.





Also, if I hold the revs up & then release the throttle it take about 5 or 6 seconds to return to idle. The cables and exterior carb mechanisms all seem to move freely, so is that an internal carb problem or the bad airbox seal ???

This could be caused by the airbox seal or it could be sticky carb floats/needles. It would be well worth giving the carbs a good clean if you haven't already.
I've given them a good squirt in & out with aerosol carb cleaner. Anything more tech than that I'll find a specialist, as carbs are a mystery to me


Thanks for your info.

Gary

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Re: GPZ400 ?

Post by Daddy G » Sun May 01, 2011 9:50 am

Is there any compatible fork set for the GPZ400 from other models of Kawasaki or any other motorcycle company?

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Re: GPZ400 ?

Post by bluespear » Fri Aug 19, 2011 9:28 pm

Daddy G wrote:Is there any compatible fork set for the GPZ400 from other models of Kawasaki or any other motorcycle company?
Sorry for delay, been away for a while.
Is it a GPZ 400s - 2 cylinders
or a GPZ400R - 4 cylinders ?????

the 400s is the same as a GPZ500s ( probably same as GPZ250 )
the 400R is same as GPZ 600 / GPX 600

HTH


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