I have just bought a 2003 husqvarna smr450. It has 500kms on a rebuilt engine wich was done by a husky dealer which cost a small fortune. Anyway i presume its running lean because it backfires on decelerition and if kept at a study rpm when driving it seems to be flooding a bit as it chokes up and then gets a bust of life. If i wind the trottle back it clears its self out and goes well.It goes like a bullet if driven hard but still back fires on decelerition. Any info on standard settings for carb tuning or info on what could be causing this would be appricated.

Backfire on decell is air leak in pipe,slip connects,head pipe, ect backfire on excelleration can be lean misfire or ignition misfire. Later George

Its normal, my 2004 does the same and so do lots of others I've heard off.

Air leak

thanks for the info.