Dec 17, 2007
#1...So I just purchased a 2001 YZ250. My 1st question is, I have a Greyish oil coming out of the powervalve drain tube. I figure this is water mixed with 2stroke oil... but where could the water be coming from? I took off the head and this model has an o-ringed head, o-rings looked okay but may be a 'lil old. Could this water be coming from the bottom cylinder gasket and getting into the powervalve? I also cleaned out the drain tube to make sure it wasn't condensation and reran the bike, it didn't solve the problem. Any suggestions???

#2... 2nd question... Before taking apart my engine, I measured compression PSI and it was at 195PSI. I am assuming this isn't a stock compression ratio. When I took off the head, the chamber is polished, not cast looking. This isn't stock right? A stock head would have a cast chamber finish right? The bore is stock at 66mm. What octane should I run with this compression?

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