backfireing through carb

[06yfz]

I put an hmf slip on and a pro design K&N kit on my wifes 06 rappy 350 and rejetted with a 145 main the stock pilot and 3 turns out on the screw as per a bunch of other riders that are near sea level, bike rungs great and has alot more power, but every so often it'll backfire through the carb and intake, not very often though... any ideas?

 

[dshiznit]

ive had the same problem a few times with my warrior and one time the filter caught on fire....

 

[06yfz]

ive had the same problem a few times with my warrior and one time the filter caught on fire....

sounds like fun lol, ever figure out what caused it?

 

[bbbthreat]

I think I have the same problem. Your filter smells like fuel right? Are you using the dynojet kit? I'm thinking it may have to do with my needle setting or just the kit. I have some mikuni jets and am going back to the stock needle to see if that makes a difference.

 

[dshiznit]

[quote:9brp6m42]ive had the same problem a few times with my warrior and one time the filter caught on fire....

sounds like fun lol, ever figure out what caused it?[/quote:9brp6m42]

lol nope but it stopped doin it after a while but sometimes when i first start it up itll have a really little backfire and after that its good.

 

[lucasislight]

yeah its running rich, i went through the same thing. dynojet uses a different numbering system than say mikuni, i would guess the 145 dynojet to be somewhere in the 155 mikuni range. so one good thing about this is when you get it jetted right it will have even more power!

 

[jasonp]

I put an hmf slip on and a pro design K&N kit on my wifes 06 rappy 350 and rejetted with a 145 main the stock pilot and 3 turns out on the screw as per a bunch of other riders that are near sea level, bike rungs great and has alot more power, but every so often it'll backfire through the carb and intake, not very often though... any ideas?

What throttle setting are you at when this happens and is the bike warmed up or cool?
More offen then not a bike will spit through the carb when it is running lean. Does it backfire on decl? If this is the case then the pilot should be turned out 1/2 a turn.

 

[06yfz]

[quote:somuvngj]I put an hmf slip on and a pro design K&N kit on my wifes 06 rappy 350 and rejetted with a 145 main the stock pilot and 3 turns out on the screw as per a bunch of other riders that are near sea level, bike rungs great and has alot more power, but every so often it'll backfire through the carb and intake, not very often though... any ideas?

What throttle setting are you at when this happens and is the bike warmed up or cool?
More offen then not a bike will spit through the carb when it is running lean. Does it backfire on decl? If this is the case then the pilot should be turned out 1/2 a turn. [/quote:somuvngj]it usually backfires at idle... its really odd. no backfireing on deceleration either

I think I have the same problem. Your filter smells like fuel right? Are you using the dynojet kit? I'm thinking it may have to do with my needle setting or just the kit. I have some mikuni jets and am going back to the stock needle to see if that makes a difference.

I dunno, havent smelled the filter yet, I'm using the gtyr kit, it didnt have a needle in it and the one in the bike doesnt have any adjustments for the clip so I was told to leave it alone, I was told also to leave the stock jets and just turn the fuel screw out to 3 turns even with the intake kit, lid off and the slip on. I'm going back out there tomorrow I think I'm gonna put the stock main back in it and mess with he mixture screw, thanks for the help guys

 

[jasonp]

I wouldn't put the stock main jet back it.. tune it rich so it misses at high rpm then back off one size at a time until it cleans up. Just that simple.
If it's backfiring at idle or 0-1/4 throttle then that is the pilot jet and fuel mixture screw. If it's lean, it will be worst when cold and pop back through the carb at idle more so then when the engine gets warm. All you have to do is back the screw out another 1/2 turn and you should be good to go. More then 3 1/2" turns out then go up on the pilot jet.

 

[06yfz]

I wouldn't put the stock main jet back it.. tune it rich so it misses at high rpm then back off one size at a time until it cleans up. Just that simple.
If it's backfiring at idle or 0-1/4 throttle then that is the pilot jet and fuel mixture screw. If it's lean, it will be worst when cold and pop back through the carb at idle more so then when the engine gets warm. All you have to do is back the screw out another 1/2 turn and you should be good to go. More then 3 1/2" turns out then go up on the pilot jet.

cool, I'll give that a shot, thanks again for the help