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View Full Version : Got a backfire when i let off ( HELP )


450rmadman99
02-10-2006, 07:30 PM
Lets see...I have a 05 trx450r w/ trinity pipe and pro design k&n i have a -4 flywheel and a brnd new dynatek programible ignition. the problem im having even before i installed the dynatek today is....when im reving it i have a popping backfire when i let off...i have a 50 pilot and a 180 main...any ideas?...oh by the way im three turns out( it does the same @2 turns or anywhere inbetween )...please help

Ken

:ermm:
AtvMxRider
02-10-2006, 08:01 PM
check for an exhaust leak
450rmadman99
02-10-2006, 08:04 PM
how the heck do you do that?
AtvMxRider
02-10-2006, 08:06 PM
Originally posted by 450rmadman99
how the heck do you do that?

Go and tighten the exhaust and then try it. If that doesn't help then your Jetting is off.
450rmadman99
02-10-2006, 08:17 PM
you see i got a 50 pilot and 180 main do you think that is wrong?
bradley300
02-10-2006, 09:30 PM
sounds like your pilot is lean
400exstud
02-11-2006, 09:53 AM
Originally posted by bradley300
sounds like your pilot is lean

Generally the simptoms that you described are those of a lean pilot.
Old Head
02-12-2006, 12:40 PM
oh by the way im three turns out( it does the same @2 turns or anywhere inbetween )...please help

If my memmory serves me right you can go another 3/4 of a turn out, going in to 2 would make it backfire. that is if we are talking about the same screw, can't remember the name offhand.
Shawn H
02-14-2006, 08:59 AM
If your 3 turns out I would Jet bigger on your pilot. You are lean, I wouldnt go any more than 3 turns before you start to loose some tension on the air fuel screw.3.5 to 40 turns and it will vibrate out.

Also Im sure the Main jet is your lean problem, Try going a little richer. Pilot is for Starting and 1/8 throttle only If I remember right:confused:
DieselBoy
02-14-2006, 12:04 PM
sounds like your lean my friend.
Shaved96
02-14-2006, 12:07 PM
Put a 195 main in and you should be set
ohsobad_chevy
02-14-2006, 03:35 PM
195 main jet, My god, I'm not trying to argue, but that sounds REALLY high.
450rmadman99
02-14-2006, 11:31 PM
ya that seams high...i did corect the backfire like 99% still have a little. wow how thing corect themselfs when you have your header pipe bolts tight...damn im a retard...so is a 50 pilot to rich now? should i go back to a 48 and maybe go to a 185 main?

Ken

oh by the way anyone have ideas for a company with good a-arms?
thanks again