New Exhaust Gaskets For The Underslung Exhausts

In my last TDR post (about fitting the underslung exhaust system) you may have seen that I thought the exhausts sounded like they were blowing from the manifold.

I spoke to the guy who actually designed and made the underslung exhaust system (martin77 at TDR250 Forum) and he recommended using some Permatex Ultra Grey gasket paste and a new set of exhaust gaskets as I had not replaced the original gaskets (or used any additional paste) when I fitted the exhausts last week.

So it was off with the exahusts which is a 5 minute job as there are only 2 springs and one bolt holding on the exhaust and 2 nuts securing the manifold.

Exhaust System Off

With the exahust (and manifold) removed, I could see exactly what gaskets were fitted.  The answer was only the paper(ish) one and not the metal gasket that should sit behind it.  I had assumed that the metal gaskets were in place when I fitted the exhausts.  Never assume anything (I guess).

Old Gasket Condition

Old Gasket Compared With New

Wot No Copper Gasket?

I then cleaned and degreased the manifolds, mating surface of the engine and the ends of the exhaust pipes.  When using gasket paste it is always wise to have the cleanest application surface you possibly can.

Degreased Exhaust Pipe

Degreased Manifold

Cleaned Exhaust Ports

Next, the manifolds were re-fitted this time with the the correct gaskets (copper and paper gasket).  I could now actually feel the copper gasket compressing as I torqued up the manifold nuts although I was incredibly conscious of shearing off a stud (Which I didn’t).

Fitting The (Missing) Copper Gasket

Manifold Re-Fitted With New Gaskets

Then 2 beads of the gasket paste were applied to the exhaust pipe (where it mates with the manifold).

Gasket Paste Applied

The pipes are made to be a close (almost interference) fit with the manifold and this ensures that the paste will provide an excellent seal.  When the pipe was pushed home there was a small amount of gasket paste that needed cleaning off and this comes off very easily with a clean cloth.

Excess Gasket Paste After Fitting

Excess Paste Wiped Off

Both Pipes Re-Fitted And Curing

The initial curing time of the Plastex Ultra Grey is 1 hour and full curing after 24 hours.  I’m writing this as they are curing, so hopefully they don’t sound quite as blowy when I next start her up.

I had been advised to leave the paste to cure for an hour then start the bike and use the exhaust gas heat to finish the curing, so that’s what I shall do.

I will report back here on how she sounds after I’ve given it a while to cure.