I don't have very much experience with engines so I figured you guys could help me on this one.

My quad is backfiring or popping during deceleration. Someone has told me I probably have an air leak where the pipe enters the engine.

I looked over it (I have a Big Gun race series) and noticed that the 2 plates that secure it are in fact somewhat loose and in the past weren't tightened down evenly so they are slightly tilted.

So I plan on loosening them and retightening them down evenly but that alone doesn't seem like it will plug any free space surrounding the pipe.

Is there supposed to be a gasket? Is so, is it obivously specific to that vendors pipe?
Do they make a sealant of some kind i could seal around the opening?

I did notice there is some gunk around the pipe entering into the engine but I am not sure if it is the reminant of a gasket that has burned off or what it is.

How should I go about fixing it?

 

Ok stock it comes with some metal like seals right in where the header goes, well mine were falling apart so I bought the highest temp resistant silicon I could find (auto store) and put some were the header pipes goes and it seems to be working great.

 

Yeah, I got impatient and called Big Gun. They said try some high temp silicon. I was thinking of taking it off, reseating it and then use some silicon on the pipe where it goes in and also at the second point down the pipe where the next piece mounts.

 

The slight popping could also be a leaning effect.......big backfires are probably something else

The factory o-ring gaskets deteriate quickly...new ones are probably in order.
Some pipes come with copper replacment gaskets,I had some aluminum ones made for my Baja

jeff

 

yes, your popping is from the header being loose ! i had the exact same situation happen to me. jetting can sometimes fool you, but just tighten up the header nuts and see if it stops like i did. i never had this happen to me on any quad. so here is what i did and it worked mint. take the header off. pull out the 2 metallic gaskets that the headers sit on. they are inside the head. get some hi-temp silicone. i used the copper stuff. put a nice coat on each side of the gaskets and replace them back into the head. the silicone will hold them. i made 2 pair of nut holders for my header nuts (i said header and nuts, ha ha) what i did was tak the flange that holds the headers on and scribed the shape onto a piece of 6061- .125 thick aluminum and cut them out into a shape of small tabs, bending one side over the flange and another over the nuts. kinda like the plates on flywheel or clutch nuts. it's been 2 weeks of hard riding and they have not budged. locktite does not work. only safety wire or nut retaining plates will cut it. making them out of thin steel would work fine too. if you cannot get it done yourself, send me a message and i will make you 4 and mail them to you.

 

cool Fuko I will try that. I can't take it apart until next saturday as my Dad stores my quad in his garage an hour drive from me.

If I can't get that to work I'll take you up on that offer and send you some cash.

Thanks again,

Jon

 

My DS came from the factory with steel crimped loc-nuts, but the aftermarket pipes usually come with cheap crap. I re-used the factory loc-nuts when putting on my pipes, and they've never came loose, either time. I also used loc-nuts on other bikes as well with good success. If you have nuts coming loose, see about getting loc-nuts, but not the nylon insert loc-nuts (ny-loc), you want the all-steel loc-nuts.

If the gaskets are damaged from not being tightened down squarely, get new ones before putting back together - they're like $2 at the dealer. They'll work with the aftermarket pipes too. Its always a good idea to replace these gaskets every time the pipe is removed, and that is why the aftermarket pipes always come with new gaskets.