I just put a pair of FMF's on my banshee. I jetted the carbs to the FMF specs....260 main and 30 pilot. Now i am backfiring. Sometimes it's actual flame comming from the silencer, other times it's just a sputter/missing sound. Once i rev it to the powerband this stops. Any ideas??? I thought backfiring was a timing issue??? Is this electrical or fuel related??

 

did it do it at all before you put the pipes on

 

Just started having the problem. Do i need to adjust the carbs air mixtures for the idle and low rpms circuts. Also how do i check timing on it??

 

I just read somehwere else on a post search about backfires that backfiring out of the pipe denotes a lean condition. Is this correct??

 

I did more searches, and they say the lean condition is in the pilot circuit, and to adjust it by turning out the air/fuel mix screw. Is this the adj on top of the TORS unit?? what are the small adj. screws of the side of the carb for??

Also, if i electrically disconnect the TORS system and leave the units physically in place, will this benefit performance any?? If not, why do people do it??

thanks

 

from the sound of it you need to sit down with your local yamaha mechanic and pick his brain for awhile. properly tuning a carb is difficult enough but two carbs is worse. the tors system is on there to keep the engine in one piece. Unplugging them will not help. People remove them all the way to get an easyer pull on the throttle, or to put on a twist. The pilot circut has it's own jet, not just a screw. be careful, you may lean out as you're testing different things and burn down. If you can find another banshee in the area with the same mods ask how they have theirs tuned.

 

What is your altitude? at Sea leel I run 320 mains. at 6000+ feet I run 240's

RoostkIng...

 

Bet it's hard to start in the condition you sit right now, too?
Put the #25 pilots back in an see what that does for you - I rejetted a buddy's '01 and had to put the #25's back in after everyone suggested we put the #30's in - we run about 550' on elevation here.

Also, what kind of filter situation do you have (stock filter, K&N filter, airbox lid off, snorkle removed, holes in airbox, etc)?? This will play a part in how the carbs are jetted, especially on your mains.

 

your running lean should be 30 pilots/ needle in the middle/ 280 to 300 with the airbox lid on/ airscrews 1.5 turns out / remember if you mess with the caps n carbs you will have to sync your carbs