Help KDX250SR 1991 F1 fitted with CR250 piston WTF??

Discussion specific to KDX models not sold in the USA
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wildrat
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Help KDX250SR 1991 F1 fitted with CR250 piston WTF??

Post by wildrat »

Help KDX250SR 1991 F1 was fitted with CR250 piston when I bought it but had blown crank seals
I rebuilt the bottom end but did not know wrong piston top end seemed ok so fitted back
Bike ran OK for a mile or so then seized up, striped top end to find piston picked up
Need to re-bore only to find that piston is Honda with steel liner WTF?
(Off a CR250 Marked Prox CR25088 1.50)
Any ideas where I can get a matching piston and as any one heard of this?
According to http://www.serco.com.au the piston I have has a difference in the height from the pin to the crown of 4mm taller from standard type so can only assume that the original owner fitted a shorter con rod?
Thanks for any help john

:prayer: :prayer: :prayer:
wildrat
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Post by wildrat »

updated have found out it is fitted with a honda TRX250 piston ?
have had honed and new prox piston
any one got what jets to recomend for it with FMF fat pipe and tail pipe
reeds ?
Franlr
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Re: Help KDX250SR 1991 F1 fitted with CR250 piston WTF??

Post by Franlr »

Hi, only posting for future reference.The KDX 250 sr and the normal KDX 250 have different pistons.One can however fit the normal piston if the normal conrod is fitted with it.
The conrod change will help if in future the piston needs to be replaced.
jgas
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Re: Help KDX250SR 1991 F1 fitted with CR250 piston WTF??

Post by jgas »

I just learned from another member that many brands copy each other and use more interchangeable parts than I ever knew. My GasGas uses some Honda parts, Kawi parts, a few KTM parts. And each of those brands can use some parts from each other. I bet Wiseco or another engine builder can help you with info on what will interchange.

My GasGas uses the same piston, pin, crank, and bearings as a 1985-6 Honda ATC 250R 3 wheeler! It had Honda parts in it when torn down. Good thing is those years 250R ATCs were very fast and reliable.
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