KDX200 Poor Cylinder Quality

[Kawadougie]

I recently removed the top end from my 2002 KDX200 to send it off for some port work and was dismayed to notice some grooves on both the intake and exhaust side.  Further inspection showed that the ports have never been chamfered at all and in fact have very sharp jagged edges.  It looks like some of the nikasil has flaked off from the port edges and damaged the cylinder.  :| The piston looks barely worn and shows no grooving whatsoever.  Has anyone else experienced this?  I may have to put an iron liner in it. 

 

[kx_693]

you can just have it repalted for about the same price as a sleeve after u pay the labor to have it put in. if u need to know of some places that do this let me know.

 

[K Dixon]

I had the same problem with my 2000 KDX220. After about a year of use I deceided to replace the piston with a Wiseco due to possible stock piston failure. I ended up having to replate because of the same damage you described. Poor quality control from the factory IMO. BTW Wiseco recommends a tighter clearance than the factory .064mm vs. .079 to .089mm. This may be contrary to what many have said about forged pistons needing greater clearances. The difference is that Wiseco also recommends removing a small amount of material in the exhaust bridge area, due to high heat and little cooling in that area.

 

[BRush]

Look at it as an opportunity. Since you need to have it replated anyway, you can use this opportunity to install an Eric Gorr 225cc big bore kit. Replating, new piston, gasket kit, PV cleaning, and porting of your choice included. It's one of the best values in performance mods around.