Why is My Honda CRF450 Backfiring Excessively?

If your Honda dirt bike backfires excessively when you let off the gas, what could be the problem?  A cracked exhaust head pipe? Or maybe a blocked carburetor pilot jet.

Partzilla’s Honda motorcycle expert John Talley hosts live Q&A sessions on our YouTube channel every Friday at 3pm Eastern. In this session, John was asked what could be causing a 2005 Honda CRF450R to backfire excessively.   

Honda Dirt Bike Backfires Excessively Q&A

My 2005 Honda CRF450R backfires excessively when letting off the gas. What is causing this and how can I fix it?

John Talley: If this is something that just happens very quickly, most of the time it’s pointing me toward the head pipe, which may be separated or have a crack in it that causes this to happen. And if this is something that’s developed over time and not just a switch that’s been flipped, I would lean more toward a partially obstructed pilot jet. So it may be time to open up the carb and take a peek on the inside. And last but not least, you may need to compensate a little bit on the air-fuel ratio for that screw. Maybe back it out another quarter of a turn and see if that calms it down.  

Watch the video below to see how to do an exhaust installation on a Honda CRF450 dirt bike.

Watch the video below to see how to clean a Honda CRF450 dirt bike carburetor.

Watch the video below to see how to do a top end rebuild on a Honda CRF450 dirt bike.

Want to see more live repair questions answered? See more motorcycle and ATV repair questions answered here.