Exhaust gasket

[sermis]

Keep having an exhaust leak from the manifold to exhaust pipe. Got a NOS gasket but only lasted maybe a week then leaked again. Used a gasket from carb rebuild kit and again only lasted maybe a week until it started leaking again. Any idea on the best gasket to use or idea on fixing it?

 

[nattieleather]

Make sure your manifold flange and your head pipe flanges are good and smooth and matting to each other. Also NAPA makes a gasket sealer for exhausts that works great! Also see if you can get the gasket material that is metallic looking like the ones used on the manifold to the head. That might give you a better sealing surface.

 

[Westech]

I had to use a new gasket and cover it with a thick beed of RTV Copper. Lasted two year so far.

 

[Whiterabbit]

Some folks have to double up and use 2 gaskets in there. From what I've seen the down pipe flange and fitting gets all warped and rotted. You'll have the same problem if you break the joint down there near the muffler too! (ask me how I know) LOL!

 

[frank8003]

Put the NOS gasket between two pieces of asbestos or "welders cloth"
Put new fasteners and torque to specifications.
Something is not lined up as it was when new and something more pliable
is needed to take up a bit of room.
In addition one could always do all that and with it use high temp sealant stuff.

 

[sermis]

I used two gaskets one time and it laster several months. I'm thinking two gaskets and sealer and just see how it works.

 

[papakb]

I was turned onto this mod by one of the local M151 guys after I told him that the manifold gasket on mine had just blown out. It turns out that Harley Davidson makes an exhaust crush gasket that's the exact same diameter as the exhaust pipe on the M151 only it's about 1/8" thick. I dropped the pipe and had to clean it up a bit with a Dremel tool but afterwards the gasket slipped right down over the pipe. The extra thickness made up for the fact that the outlet flange on the manifold and the pipe inlet weren't parallel to each other and left a small gap toward the outside when clamped together. Take your old gasket with you to a Harley dealer and ask for an exhaust gasket with the same id. They're round instead of diamond shaped but it worked like a champ and hasn't leaked yet!

Kurt Lesser