Utility quad backfire

[daBIGstuff]

I know its a 4 stroke, but my nieghbor wants me to find out what is wrong.

It is a Suzuki 500 Utility quad. It runs fine, the only thing is when he shuts it off seconds later it backfires, it sounds like a gunshot. this happens every time it gets shut off. he tried a few things like let it idle awhile before he shuts it off, still does it. he tried revving it then shutting it off but still does it. it idles and runs fine, i am not shure what it is. this also happens year round to.

[4x4kingx889]

go to http://www.nyrocatv.com/index.cgi