Bub exaust system made Yfz pop and crack.

[speedy]

I put a BUB exaust on my 04 yfz450 and im running a 185 main jet , it ran great with the old Big Gun exaust but now i guess that jet is to big for the BUB system because now it pops and cracks when you rev it 1/2 throttle, what could be the prob?

[Colby@C&DRacing]

What needle are you running the bub system asks for a specific needle.

[daman02]

185 main does sound a bit rich when compared to jetting for most exhaust systems. You might try stepping down to about 165-175 depending on what else you have done performance wise.

[speedy]

What kind of needle does it ask for on the BUB system?

[speedy]

Im running a GYTR needle.:cool:

[400exrider707]

What other jetting changes have you made besides a main and needle? What clip is the needle on?

[speedy]

I have somhow got the jetting rite on tap now , i am running :48pilot-165main-needle on 3rd notch down.