garry@floyd.UUCP (06/28/83)
backfiring under deceleration is often a symptom of innacurate ignition timing. if the timing is too far retarded it will cause this. what happens ( i think ) is that the spark fires too late to burn all the fuel/air mixture before the exhaust valve opens, so some of the combustion is taking place in the exhaust pipes. i had this problem with a 1970 bmw 750 motorcycle, and a good tune up, including setting the timing, fixed it right up... garry hodgson BTL whippany floyd!garry