little help with engine backfire

[kidloco33]

I have recently developed a backfire whenever I am shifting down in gears. I am running a completely stock quad and have never had any problems besides some body damage. Any help would be greatly appreciated as I am not the most mechanically inclined person. Thanks!!

[Jimbo M]

Could be an exhaust leak where your header comes out from the cylinder. We had a leak there - can cause a backfire.

[bustedknuckle]

exaust sounds like thats the prob.also how many hrs on it ? may be valves .

[sw1tched]

exhaust issue, or did you take the airbox lid off / spart arrestor off? may be running a little lean...