starter back fire/ jetting?

[bonecrusher69]

I have a 03 WR450. I did all the free mods and replaced the main jet with a 168. The starter jet is drilled to .028, about 2 1/2 turns on the fuel/air screw. The bike starts instantly but a split second before it starts there is a sharp snap like sound from the exhaust. Other than that the bike runs great. any ideas out there. ? Thanks

[Indy_WR450]

Buy the JD jetting kit from this forum's store and follow his basic instructions. You will be happy with the results. Backfiring will be minimized. I do not recommend drilling jets. Buy a 48 pilot jet and a 72 starter jet as well. That should complete your jetting needs year round. ?

[bonecrusher69]

Thanks Indy I'll do that, ?