Manafold leak ? 1098 ,1970 minor

[lambrettalad]

Hi Just taken my moggie into National tyre to check what I thought was a leaking exhaust. Their finding was nothing wrong
But when I drove home i still thought it was leaking ,so I got my much better half to block the exhaust pipe,whilst I listened and heard a hissing sound from the exhaust side of the engine. I've had a look and there doesn't seem to be a gasket.Is it missing or what seals the mating faces? Any help much appreciated .

[simmitc]

Blocking the exhaust would certainly lead to back pressure! There should be a gasket between the manifold and the head. It's a heat-resistant material rather than paper, but if it's missing then I'd expect air leaks on the inlet as well, leading to poor running.

Is your air filter complete - the tube pointing away from the base has been known to fall off, and it changes the note very noticeably.

[lambrettalad]

thanks for that I'll have a look tomorrow