My 83 Big Red does small backfires only when decelerating like when going down a hill. I though it might be the carb so I sprayed carb cleaner and it didn’t help any. I was thinking it might be the timing but I don’t know how to change the timing. I use my trike for hunting and the backfires tend to scare the elk and deer. Here in Washington it gets dry in the summer even though I have a spark arrestor I don’t wanna start the next forest fire. Any help would be much appreciated.