1973 Bonneville exhaust headers

[Oggers]

If you have to apply pein hammer, cement, paste or silicone to prevent the exhaust at the head from leaking, then it's a poor design in my view.

Hence my comment that Triumphs are temperamental beasts. When sorted they are fine enough, but my gearbox is still rubbish.....

[R]

Heck, I've applied some or most of those to bikes cars planes and boats at some point.
What does that say then !

Old machinery rarely conforms to the modern fit-and-forget philosophy.
And throw it away if it doesn't ...

[Rex]

Then there's the older Japanese method where a large clamp holds the pipe in the head, and is secured by two dinky 6mm MS studs; quick and cheap at the production stage but bloody painful on an old four-pot that's had numerous heat cycles just to make sure those nuts aren't ever going to unscrew again.

Or the very fine threaded port in the head, as with some Nortons and poxy Morini's. Unscrew the gland nut and see half of that fine thread unwind with it, and that's always great for a hearty laugh when that happens.

Nope, I'm OK with the push-in design as used on many other bikes and not just later model Meriden Trumpets. At least it works and carries on working.

[Oggers]

There is a fundamental difference in repairing something  - inevitable with old machinery for sure - and fixing something that was a poor design in the first place. Push in exhausts are (to me anyways) poor design, as are pressed steel chaincases with the rubbish band seal, flip up side stands, placing electrics where the bike gets wet etc etc.....

[iansoady]

The fine threaded port on Nortons is fine with a cast iron head - indeed mine was solely responsible for holding the exhaust on for some miles after the silencer bracket - aftermarket item of course - fractured. I admit that it could cause problems on the alloy Commando head but usually because people didn't keep it tight enough.

[Oggers]

Never had any real issue with exhaust headers on the many Jap bikes I have had. Couple of broken studs, but replaced easily enough. Nuts can slacken off slightly, and where that happened I simply lock-nutted it. Personally I think they make for a decent, tight, compression fit with the hollow copper gaskets.