Motorcyle Repair Recommendation

HomeWood · 09-18-2014, 12:53 PM

Might be a carb issue. That backfire sounds like gas fumes igniting in the exhaust. My commercial mower does it if I shut it off during higher rpms. The motor is still sucking gas in as it cranks down (with no spark) and sending raw fuel/fumes into the hot exhaust. Then boom!

It could also be gas igniting in the combustion chamber when the key is turned off. Same thing as exhaust, it's still hot enough in there to ignite the gas.

Tune up, cleaned carb, and running higher octane gas may very well solve this.

09-18-2014, 12:53 PM	#7
HomeWood Senior Member Join Date: May 2006 Location: Clayton,NC / Sanbornton,NH Posts: 611 Thanks: 126 Thanked 137 Times in 75 Posts	Might be a carb issue. That backfire sounds like gas fumes igniting in the exhaust. My commercial mower does it if I shut it off during higher rpms. The motor is still sucking gas in as it cranks down (with no spark) and sending raw fuel/fumes into the hot exhaust. Then boom! It could also be gas igniting in the combustion chamber when the key is turned off. Same thing as exhaust, it's still hot enough in there to ignite the gas. Tune up, cleaned carb, and running higher octane gas may very well solve this.