I was hoping someone could help. My 2001 Savage backfires everytime I shut it off. What could be the problem?

The pilot screw adjustment will fix that. You'll find lots of info on it with the search function. Mine's out (counterclockwise) 1 1/2 turns, no backfires.

For a short term fix, leave the bike in gear and let the clutch out enough to put perssure on the gears as you hit the kill switch.

Does anybody know why my bike backfires@startup?  When I got it (last year)it backfired on shutdown(sometimes) than (this year)I installed a SE muff and put in a new sparkplug (normal heat range) and now it (sometimes)backfires when I press the start button..  Button in = PAAAAAANG like a really loud gunshot. What could be the reason for that?    it also backfires when going down hills but nothing at shutdown.....

LS650 . 1997 .  40000 km

I'm the third owner...  The women I bought it from did not know anything about it, she had bought as a "reward"(when she stopped smoking) but didn't ride it...the interest was just not there..  But she told me that previous owner had been an active motorcyclist and had used it on several trips down in Europe(did explain the high milage.).   The mixture screw is in the open so there has probably been some modifications, the tank has come off many times( scratches on frame where the petcøck is)  ...  don't know if  jet mods have been done..  
It's just this PAAANG at startup that I don't understand   .. the the backfire at shutdown can be explained by unburned fuel  ..  but when the bike has not been moved and then when I push start it (PAAANG)  the should not be any fuel in there?  Right?