jetting or general carb problem?

[Raptor350yamaha]

When i first got this mojave a year ago the filter had holes burnt in it and bugs and dirt in the gas tank. since then i rebuilt the topend and got a new filter and cleaned the tank/fuel lines and the carb a little bit. it runs ok but when the airbox boot moves a little off the carb just so there is 1/4 inch gap it runs pretty good. if i put it on again and tighten the clamp really tight it runs terrible. it has a DG exhaust but i dunno if they rejeted or not. im not sure what the problem is tho. anyone know?

[markvette]

if it runs better with the boot off sounds like the main is too rich. try to go down on the main. if you dont make sure you keep that boot on you will be doing a top end real soon. dirt will get into the cylinder and mess it up .

Mark

[Raptor350yamaha]

thanks. yea when the boot is on really tight it revs slow and cuts out at 3/4 throttle. i keep it on it just falls off every once in a while.

[Raptor350yamaha]

i ordered a FMF jet kit today. i think the main is fine from what i have read. with boot all the way on if i crack it WOT it lags behind and slowly (very very slowly) revs up untill it gets up to 3/4 throttle and revs a quicker(but still not normal). is it the needle and pilot jets? should i go down on the main as well. and by the way. i remeber when i got it broke in i changed the plug and it was black so does that mean its too rich? i turned the fuel screw all the way out and it helped some.