Hi all, am absolutely sickened with this but its done now. I fully rebuilt my YZ250 motor (mains, rod, piston, seals), put all back together and ran it in. Raced three 20min motos on sunday, bike went great in all of them. Got home then remembered that I never tightened the air boot (airbox side) onto the carb after I put the engine back in. I removed the rear subframe assembly last night and had a look at the carb, all is clean except for a bit of dusty residue at the recess machined in the bottom of the carb. The boot was intact on the carb but I'm assuming that it has taken in dust now. Has anyone done this before and got away with just stripping and rinsing the motor out, should I even bother to look or assume it scrap and just order new bearings now ??? I guess I know what I should do but am just wondering if anyone has done this before and what outcome they had. Thanks. Cir.