Backfire on deceleration

I have a 2001 suzuki volusia VL800 that just recently had the engine replaced . i am finally road testing it and when im at speed and either let off the throttle or down shift to decelerate i get some good backfires . it doesnt happen every time but it is very frequent . any ideas what may be causing it ?    

I ride a '99 V Star 1100 that I got a little over a year ago, and had a similar problem with backfiring and popping. The previous owner installed Shogun Ripsaw pipes (which sound great BTW). But when you install aftermarket pipes, a lot of times you have to switch, I believe, it was the jets from the front cylinder to the back. My friendly local bike shop did the switch and installed a larger jet in the back cylinder (I think it was), which eliminated the problem. Guess that's a long way to suggest maybe it could be carb problem, assuming you have carbs and not EFI.

Good luck. Ride safe, watch out for cagers on cell phones, and thank The Man Upstairs for every safe ride.  

My wife's Savage also backfired on deceleration. The problem is in the idle, and pilot circuit. For emissions, they are set a "little" lean.
Get those 2 adjusted, and your problems are history.
Swap out the exhaust, and "little lean" is now "really lean". Same problem.  

Come to think of it, I think my bike guy mentioned that it was running lean, too. The larger jets he installed fed it more juice and I think helped remedy the rpoblem.

Good luck.  

I JUST BOUGHT A NEW C90 BACK IN APRIL W/SIMILAR PROBLEMS. CHECK OUT MY POST IN THE(MOTORCYCLE ENGINES)FORUM ON THIS SITE. MY POST IS -jerryk90 VL15000T C90 SUZUKI- LET ME KNOW IF YOU HAVE ANY OF THE SAME SYMPTOMS. I'M CHECKING ON OTHER SITES,IF I FIND SOMETHING I'LL LET YOU KNOW  

check out reply from CapnIcthus to my post in motorcycle engines.