Backfiring Banshee

[Oldschoolyamaha]

Hello all

I have a 92 Banshee, It is a bear to start but when I get it started is runs fine at normal speed. It is a completely rebulit stock motor with Toomey T-5's. When I go wide open throttle it backfires and boggs. I have taken it to the dealer, they checked the stator, which is good. The carbs are jetted according to the specs, the needle is in the 3rd postion. I have good spark from the coil. New reeds. New air filter. It has good compression. My spark plug is a light choclate brown. This has stumped my delaer and I am at a loss. Any suggestions would be great. Thanks Oldschoolyamaha

[flotek]

thsi is usually your banshees way of telling yo u it needs more fuel and a clean fresh non obstructed air filter while your at it .is the flywheel key partially sheared ?what jets are in your bike now?

[Oldschoolyamaha]

It has the stock pilot and a 300 main. The air filter is a KnN that is clean. I will take a look at my flywheel key. The bike was running good the last time that I rode it last season, Now this..

[banshee balla]

i would go w/ a larger pilot...on the bike....my bike backfires to when im going open throttle....never really thought to much into it

[flotek]

sounds like it isnt getting the proper air/ fuel ratio(carb jetting) or its out of time (flywheel key)

[fast350]

i was gonna say check the flywheel

[Yamaha_Freak]

this happened to me..go to 30 pilot jets..i am 99% sure that that is the problem

[bansheeadam]

i run 32.5 pilots you could try that too depending on the elevation. This may sound stupid but make sure the slides in the carbs arnt in backwards because they will fit in 180 degrees backwards.

[Kane]

You're half right, they'll fit in the opposite carbs backwards but not in their own carb backwards. I.E. the left will fit backwards in the right carb but not in the left because of the guide slot cut into the side of the slide.

Try dropping down to a 270 main to see if it improves.