backfire or pop when first start

[01440ex]

when i first start it b4 it will start i get a backfire or pop out of it...any ideas does it mean im to lean or to rich...i got a 170 main and a 50 pilot....stock needle never understood what a adjustable one does for me...some help would be great thanks

[Ride1Rob]

Timing being slightly off will cause it to pop as well. But I'm not sure if it'll run with it one tooth off so that may not be it. That pilot jet is really big though. Probably overloading the carb with fuel with that big of a pilot and the mods you have.

[01440ex]

i just got the quad...the guy i got it from said the timing was retared one tooth...said yamaha did it for him told him it makes it run better...im thinking of fixing it but im not sure how to do it...ive done it on my 400ex but not this...it has a k&n filter with a slip on exhaust also has a higher compression piston but stock bore

[jr4]

does it do it every time or only cold

[01440ex]

only on first start up when it is cold...sometimes when warm but maybe just once twice

[jr4]

I would start with cleaning the carb and check he neenel jet and seat also if you don't know how long it has been since the valves were checked check them and replace the spark plug also did you by the bike in the same area or was the elevation diffrent

[coryatver]

Originally posted by 01440ex
i just got the quad...the guy i got it from said the timing was retared one tooth...said yamaha did it for him told him it makes it run better...im thinking of fixing it but im not sure how to do it...ive done it on my 400ex but not this...it has a k&n filter with a slip on exhaust also has a higher compression piston but stock bore

That is a pretty normal mod for these quads that shouldn't be your problem