'81 exhaust leak at head

[born loser]

hey all!

So both cylinders are leaking on my '81 400 at the moment. Lots of gas escaping at the collars. Im using '79 headers that are chopped just before the mufflers and ive welded on straight pipes. Ive got the two piece "spacers" in and the collars seat down snug. Is it possible '79 pipes are in fact a different part to the '81 pipes? I didnt think yamaha changed the exhaust set up between those years but I could be wrong. Could it be possible that the gas is somehow escaping between the inner pipe and the outer sleeve? Im not losing gas along the exhaust anywhere else, just at the head. Ive doubled up on gaskets, used heat wrap, triple checked all that all the pieces are fitting together right (btw wiring those two "spacers" in position with safety wire is reaaallll helpful if your fighting them staying in place right now) all to no avail. Any ideas from you 400 pros out there?

 

[xschris]

Only use one new copper o-ring at the head per pipe. Also make sure the pipes are lined up flush with the head. If they are off at an angle a little they will leak. Using custom pipes that don't use stock mounting points at the back will make it harder to line stuff up.

 

[born loser]

Ive since pulled out the second exhaust gasket, I just wanted to see if maybe it wasnt sealing properly or something. Yeah I never realized how much those stock mounts actually line everything up and pull it all tight together until I cut them off!