need help

Well i cannot get my 2002 Yz426f jetted right. When ever you are going the throttle like 3/4 to closed the bike backfires near every time the engine turns over :thumbsup: this is with the stock settings after i personally resealled the exhaust system. So I jumped up to a 48 pilot jet which worked good which means it backfired little and did not bother me. But the only problem is to start the bike cold i needed to pull out the hot start otherwise it would not start and i and at 0 elevation at 65 degrees. So I thought that meant the pilot jet is to big so the next idea i have is to get a smaller pilot air jet so it does not get so much air. The pilot air jet is at 100 and the main air jet is at 200 and i just changed everything back to stock. so my question is is there any thing you guys can think that would cause it to backfire so much or shouuuld i go back to the 48 pilot jet and call it good? I have not changed the pilot air jet but sure am thinking about it but really i don't know what to do :thumbsup:

Dude if I had to guess I would say it is getting to much fuel, sounds to me like its running rich. Change that bad boy back and dont mess with the air side. Think of it this way.... without being able to adjust cam timing you get to much air and fuel in to the combustion chamber and no way to get it out. Thats my 2 cents. Try it out and I'd be interested to see what happens.

the bike ran horrible stock the best it ran was when i put in the 48 pilot

Go back to 48 pilot, it should be better.

if i go to the 48 pilot is it okay to use the hot start to start the bike cold

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