91 CR250 150psi ????

[mifun3]

Well, rebuild my brothers bike (a beater that we fixed up) Changed crank bearing, all seals gaskets and replaced piston and rings (67.55) had cyl honed and mesured to make sure cyl was not oval. Mesured rings and drilled lube holes in piston where exhaust bridge is. Installed rings in proper location with facing up even know wiseco says it has no importance. Lubed rod bearing and cyl rings and cyl walls upon assembly. Cleaned carb...

Now my story!! Started the bike up was running perfect went for a small ride did about a mile bike stalled (didn't seize) Tried starting it with kicker no luck. Plug nice tan color but dry. Was able to start it by compression and rode it back with less power. Back home did a compression test 150 My 02kx250 is 200psi++

Any ideas what could of happened???

Thanks guys!!!

 

[wornknobby]

well, how big were those holes you drilled in the piston? b/c if they are too big the exaust will escape too soon at low rpm's, unless your holes are helping the transfers, but i beleive you said it was on the exahust side.

 

[mifun3]

Exhaust holes were drilled as per Wiseco specs (actually called them direct cause this was the first time that I had heard about the drilling lube holes)

I would think that this shouldn't affect compresion cause the holes are under the rings in the sleeve???

Thanks

 

[mifun3]

anyone???

 

[NacNac250F]

Theres a lot of stuff you need to check. Head gasket, base gasket, did you put the piston in backwards, spark plug loose, crank seals, are the ports chamfered-> if they arent the rings could wear real fast. Pull off your pipe and look into the cyinder with a flashlight, see what the piston looks like, and check out what you can see of the cylinder walls.