2000 fxdwg k&n vance and hines pipes but everything else stock. performance is good, idles good, but backfires thru exhaust when throttle is reduced..
too much fuel? smaller jet? don't ever let off?

thanx in advance

 

Plugs appear to be running lean? as well so?

 

Did you install slip ons? Did you reuse the clamps or put new ones on? Might be exhaust leak.

 

no they are 1 piece nice pipes..it is carbed so will take it offf tommorrow and check jets

 

Popping on deceleration, it is running lean.

 

thanx mike i think your right!

 

Check the pilot jet and go one size larger. Mine was a 45 - went to 49. Set the idle jet to 2.5 turns. Tune from that point.

Also put a shim under the needle in the throttle slide, about 0.050". (one hardware-store washer).