Z550 Cylinders, pistons and head on Z400J bottom end?

MrGMoto wrote:

Thanks for the info! got a question, I can only track down 3 oversized pistons. would it be possible to use 3 over size and 1 standard ? or would this unbalance everything ?

 

It's been done before as a last resort but not really recommended although i have had engines in that have had similar done ( 3 stock and 1 OS ) and were running just fine.
The OS piston would need weight matching to the others at the very least.
 

okay, thanks, I can get 3 O/S but can't find a fourth so was thinking of doing the 3 O/S and 1 standard  or 2 standard and 2 O/S.

MrGMoto wrote:

okay, thanks, I can get 3 O/S but can't find a fourth so was thinking of doing the 3 O/S and 1 standard  or 2 standard and 2 O/S.

What model pistons do you mean , 400,500,550 ? and why can't you use 4 std if you can use 2 .

It may be worth searching some of the Japanese websites for pistons - due to taxation and insurance brackets 400's where hugely popular in Japan (hence the flood of 400 imports to the UK in the 80's - GSXR's, CBR's, ZXR's etc) "cruzinimage" don't list them but probably worth an email?

If your going to all this trouble and can afford the cost used good forged pistons = Wiseco 615cc kit

You get a nice bump in compression and some tougher pistons.

Instead of starting a new thread I can ask here maybe?

Would it be possible to put a 400 crank in a GPZ550 engine to make it 500cc?

Kr Sixten

Sixten wrote:

Instead of starting a new thread I can ask here maybe?

Would it be possible to put a 400 crank in a GPZ550 engine to make it 500cc?

Kr Sixten

Yes! but you will still need to shorten the 550 block and use a shorter camchain etc.

The machining is no problem.
It should be possible to use the 400 cam chain I guess?

Would make a cheap and hopefully powerful and reliable 500cc race engine.

I found this engine en Europe. 
www.motorparts-online.com/en/kawasaki/gp...994/engine/201523834

Says it’s 1989-1994 but it looks the same to me. Does anyone know if it’s the same?

 

Sixten wrote:

The machining is no problem.
It should be possible to use the 400 cam chain I guess?

Would make a cheap and hopefully powerful and reliable 500cc race engine.

I found this engine en Europe. 
www.motorparts-online.com/en/kawasaki/gp...994/engine/201523834

Says it’s 1989-1994 but it looks the same to me. Does anyone know if it’s the same?


 

That will do the job for the bottom end.
They all use a hyvo camchain so which ever combo of parts is used the 400 chain will be needed.


 

Thanks for all the advice.
Maybe this can be a winter project for next season.

Hi again,

I found a 400 engine. Now I’m looking for a GPZ550 motor to donate pistons, cylinders and head for the 400.

What engine numbers would be the most powerful GPZ550 engine?

I remember reading somewhere earlier that the 84-85 engine had the best pistons/cams/head but I can’t find that now. 

I found that engines starting with ZX550A have the best pistons. Unfortunatly not sold in Sweden. But I found a KZ550D engine that I believe is second best piston and cylinder donor