Compression Q.

[Zakradu398]

How high can one go on a stock unwelded crank?

[CJM]

Dunno truthfully.

But the higher comp you go the more chance you have detonation unless you use race gas. I never saw more than 12:1 offered for an EX either.

[DragonGunner]

Think Wiseco sells 12.5:1....have read of some 13 and one that was 14 that raced alcohol. Most likely they had a beefed up crank though...not sure. LOL....I actually ran the 12.5:1 in 440 on my EX at one time, stock crank held up just fine, however the stock studs didn't hold up, kept blowing gaskets. Went to GT Thunder studs.

[DragonGunner]

http://www.exriders.com/vbb/showthread.php?threadid=225338

[gasguzzler]

I've been running a 12:1 piston up to 10,000 rpm for the last year on a stock untouched crank/rod on race gas. I think the rod will fail before the crank would need to be welded.