200 - 225 Conversion Questions

19Brendan81

Member
Mar 6, 2005
153
0
Hi Guys,
I have a 91 KDX 200 that isn’t far off needing a rebuild. The bore is in a sad state, with some cracking between the exhaust ports (not very deep). The nikasil lining is worn through down the bottom. So I figure that If I am going to be spending a heap of money getting the 200 re lined, then why not go out to 225! I have heard that this mod will give a significant increase in power and would be interested in hearing from people who have done this. I also would like to know what the new piston size is, and what its out of…is it just a common aftermarket size? How much does this cost you guys in the states? ( I am in Oz). If its going to work out significantly cheaper I would be keen to post the bore over there and get it shipped back. Any thoughts or advice would be much appreciated.

Brendan
 

m0rie

Member
Nov 18, 2002
469
0
If only it were possible. You can't do a 225 punch out with the 89-94 KDX's. The powervalve is too close to the piston to allow it.
 

Brettsauto

Member
Jul 4, 2005
15
0
Hi Brendan,
I bored my 200 out by 2mm and fitted the standard size 220 piston (wiseco). Plenty more bottom end. Electrosil in Vic, did my barrel and supplied the parts.
Regards Brett.
 

19Brendan81

Member
Mar 6, 2005
153
0
Oh that is shattering. Is it the main valve that is the problem Morie? How many mm do you need to go to get out to a 225.

Thanks for you advice Brett, out of interest how much did it cost you?
 

Brettsauto

Member
Jul 4, 2005
15
0
Can not remmeber the price , It was not cheap, the big bore was only $80 on top of the re nikasil. They can modify the exhaust valve too. Give them a call 03 9435 7029, they will have all the prices and want you can do. I have one guy who bored and stroked his 200 to 250
 
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