Dirty Motor

T

Toothy

New Member
Hey guys,
I was wondering if black build-up on the engine around the exhaust port is just normal or do I have a leak. I’m guessing I have a small leak but it doesn’t seem to affect my ride. I’ve tightened it down but it still fouls after a little while.
 
a.graham52 said:
sounds like a leak. get yourself anohter gasket and swap it out.
Click to expand...
Ditto.
If the gasket isn't sealing you'll get what you're having. Here's a hint. The exhaust flange where the gasket sits is usually warped from the welding process at the factory. You need to sand/grind the flange flat to make a good gasket surface.

Remove the pipe from the engine. Clean the gasket surface so there is no old gasket material then 'paint' that surface with magic marker, or machinist dye, even a light coat of paint will work. Now run that surface over sandpaper placed on a known flat surface such as glass. Just a few swipes will do. You'll quickly see where the high and low spots are. Eliminate them. They are what cause a bad sealing surface. You can tighten the fasteners all you want but if the gasket surfaces aren't flush it will eventually leak.

Make a new gasket from gasket material made for exhaust applications. I like 1/8" minimum thickness. Tighten the fasteners then check them again after a couple of heat/cool cycles. Torque is about 60 inch pounds. Good luck.

Tom
 
I agree... the exhaust flanges are usually the culprit here and making sure teh flange is flat and true as well as properly torqued will stop any leaks once a new gasket is installed. If you can get the flange perfectly flat you could even use just a very thin layer of high temp rtv and it'll seal just fine
 
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