KDX Exhaust Leak

[Muskeg Man]

I have noticed some fuel/oil leaking by the o-ring seal where the exhaust expansion chamber meets the block. Will this effect performance? I am having problems with the jetting, could this be the cause?

 

[Trick24]

If it's not jetted right you will get splooge out of there. Depending on how much a leak you have there will affect performance. Try replacing the oring and fix that if it is bad, and that may also help with your jetting problems.

 

[m0rie]

Last time I tore my 89 KDX 200 down the expansion chamber and the block didn't want to seal up. Swapping on thicker diameter O-Rings and a smidge of high temp RTV silcone sealer around the opening fixed the problem up good, and as an added bonus seemed to give back a little bit of snap in the throttle.

 

[Canadian Dave]

Yes a leak form the header section of the pipe will certainly throw off your jetting and you'll be missing out on some power.

I'd suggest removing the pipe and cleaning it up the end on the pipe well using something like carb cleaner, varsol etc and clean the cylinder well where the pipe is inserted. Make sure the two o-rings on the pipe are intact and run a small bead of silicon between the two o-ring. When you reinstall the pipe the silicone will stop the leak from coming back again. Any silicone will work; it doesn't have to be high temp.

While you have the pipe off check and ensure the copper gasket between the pipe and cylinder is still there and in good shape.

David