Oct 30, 2007
hey guys, new to bikes not to 2-strokes. i just bought an 01 cr 250, this will primarily be a woods bike both single track, and open quad trails. i want to boost the bottom end and try to smooth out the midrange hit. ive searched here, and on other sites on this topic. i still have some unanswered questions. my current mods are SST pipe, and boysen rad valve. 10 oz flywheel weight is in the works. ive read a lot about the thinner base gaskets. im not too excited about that. it seems like the compression would be minimal. i think it would just be better to have your head re-cut. how much compression is normal for a woods bike. i realize monster compression could be a PIA kicking it on an already difficult off camber. for those that have actually tried the cometic gasket about how much extra compression could you expect. i assume stock is in the 180ish range. i appreciate any advice on this or any other simple low end power tricks i may be over looking.


Jun 6, 2007
Congrats on the bike. I bought the same one in May of this year and I love it.

When I first picked it up it was a slug in the low revs. Did some research (on here) and realized this particular model was jetted WAY too rich from factory. I had to go one size smaller on the pilot jet and switch to a s-7 nozzle. After that it was like a whole new bike.

Good luck.


Jul 31, 2002
The thinner base gasket is also for retarding the port timing, moving the power down the rpm range.

You could try also advancing the timing a little

Most likely that 10oz FFw will do the trick
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