While the UPP boots are a good idea, I would not use them too cover up an existing lean condition. Worm clamps from the local parts store work better than the stock clamps too.

 

I'm getting those pilot jets GaryC suggested when the shop opens tomorrow. Maybe different clamps too. I can just see it if those things blow off clear back at Devil's Dune when Valerie's riding it. She'd make me drag that thing out with a towstrap tied around my nards.

 

GARYC660R-I agree that you must first deal with the issue of a backfiring motor no matter the cause but the carbs on a totally stock raptor have been known to blow off so i beleieve that the upp boots would be a good upgrade in any case.