POPPING THE QUESTION
Q:In Don Canet’s piece on aftermarket slip-on mufflers (Evaluation, “Yoshimura Signature Series Alpha Slip-on,” Jan./feb.), he mentions: “…the annoying deceleration popping sound that can occur after modifying a bike’s exhaust.” What actually causes this? Is it because there is a leak? Even so, what makes the sound? Are the popping sounds miniature backfires?
A:Hey, Dave. Ask questions, don’t answer them! Yes, the popping sounds are small “backfires,” which is really uncontrolled combustion that is occurring in the exhaust pipe. Anything that reduces backpressure will allow this to happen. A crack at the head pipe is the worst.