Question about Yamaha YZ 450 F Motorcycles

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2007 yamaha yz450f... while riding last week it was backfiring on deceleration. it blew a 5 inch hole in the header pipe. i purchased a new one, cleaned the air filter, changed the oil and put a new spark plug in it. now it is still backfiring on decel and the header pipe was glowing red... Why?

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  • 191 Answers

Exhaust leaks near the exhaust port can draw air into pipe on deceleration and detonate any unburnt fuel leaving engine, causing backfire and high temps.
An overly lean fuel mixture on the engine can make decel backfire worse too.

Posted on Mar 13, 2011

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4 Answers

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