[stock compression ratio, 300ex] - ATV Riders Forums - Honda, Yamaha, Suzuki, Kawasaki, Polaris, CanAm, Arctic Cat, Kymco ATVs

Pages:1

stock compression ratio, 300ex
(Click here to view the original thread with full colors/images)

Posted by: ssduane

Anyone know the stock compression ratio of a 300 ex?

Just picked up a Wiseco 11-1 for mine and was wondering what the increase would be.

Posted by: dork

8.9:1

Posted by: ssduane

wow, I figured it would be in the mid 9's, guess the 11.0 comp piston along with a .020" shaved head should make for a nice power increase.

Posted by: bwamos

Yep. It's a very noticable increase.

w/ the 11:1 and your already shaved head.. you may need to mix a bit of race fuel on occasion.

Posted by: ssduane

Got her all back together. Haven't had it out at all, put a new cam in, did a cam break in and ran it up and downt he street a little. It needs a race gas mix, pinged all over the place with 89, did a 1/3 mix with C12 and she sounds sweet, not to mention the increased throttle response.

Will take it out the day after xmas for the NY's week/weekend