05 450r backfire

[honda4life72]

ok got a 05 450r . ported head, cp 12:1 piston. full curtis sparks big core exhaust, esr intake. stock carb. it back fires about every time i go to kick it. atleast once it backfires. but while riding it it never backfires. its got a 185 main. and i'm not sure but the clip is moved 2 notches up or down. i cant remeber. from stock. stock pilot. any ideas?

[exrider12]

Bump up the pilot to a 48 or somewhere around there and get a 55 leak jet. Should cure it.

[d3ktrix]

Originally posted by exrider12
Bump up the pilot to a 48 or somewhere around there and get a 55 leak jet. Should cure it.

Stock pilot is a 48 in the 05's and he's running the stock carb so I don't think there is a changeable leak jet.

If the pilot was the problem it would be popping on decel while its running also.
Doesn't mean its not the problem though.
With a setup like that a 50pilot is more common.

Are you hitting the throttle before or during kicking it? Sounds like unburn't fuel in the exhaust when you kick it.

[honda4life72]

like i have done sense i bought it . one pump of the trottle and two kicks and it starts right up. just now with all the mods it backfires during one of them two kicks

[the Z Man]

Pilot, recheck your valve clearances, might even try a 52 pilot.

[d3ktrix]

Try not pumping the throttle anymore before you start it a few times.
Easy test before you start pulling things apart.