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s type exhausts

Discussion in 'Norton Commando Motorcycles (Classic)' started by colin davie, Oct 7, 2018.

  1. colin davie

    colin davie

    Joined:
    Jun 16, 2018
    morning all,
    i have s type hi level exhausts on my norvil mk 2a and the left side has broken just as it enters the head twice now . the exhaust clamp is always tight and the rear rubber mount is good , is this an issue with these exhausts ?, the isolastics have been checked so the motor is not bouncing around too much , any similar issues out there ?
    colin
     
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  2. rivera

    rivera

    Joined:
    Dec 13, 2014
    Same on my bike, someone told me to not tighten the muffler clamp to much so there is some play.
    I now have an Andover Norton pipe which looks thicker than the Campells one I had mounted earlier.
     
  3. colin davie

    colin davie

    Joined:
    Jun 16, 2018
    rivera ,do you replace the copper sealing washer every time ?
     
  4. tomspro

    tomspro VIP MEMBER

    Joined:
    Jan 25, 2014
    Hopefully DogT will see this and share his considerable "s" machine knowledge with you.
    BTW - isolasics do not reduce engine movement, that is the job of a good headsteady.
     
  5. rivera

    rivera

    Joined:
    Dec 13, 2014
    Did so last time
    I am referring rather to the clamp between the exhaust pipe and the silencer.
     
  6. DogT

    DogT VIP MEMBER

    Joined:
    Jan 20, 2009
    My original RS header fractured right at the front at about 10K. I brazed it shut at the time in the 70's. I haven't got enough miles on the latest ones I got (from Xanders in Ohio) to say if they last, but yes there's a lot of stress on the S type headers. I actually took a long bar and bent the new headers to fit better on the silencers above the primary chaincase. I tried to put everything together with as little stress as possible. I couldn't stand the leakage of exhaust on the panels so I got 'Moose' clamps for the header to silencer joint and clamped it down tight. If you let the exhaust system get too loose, it will beat up the LS panel plus the 1/2" iso nut and the shields will vibrate loose. You will burn your leg at some point. There is a mod to give the dog leg bracket a bit more give if anyone is interested in it. I've never tried it.

    Realize, you newer Norton owners, that under hard braking, the larger front mudguard/tires will foul in the S exhaust headers and prevent you from steering. That's why the 69/70 had a 310-19 front tire and shorter stays, bridge and smaller radius guard.
     
  7. colin davie

    colin davie

    Joined:
    Jun 16, 2018
    Dog T ,you are right about how close it all is to the primary case and that rear iso mount nut ,also my front fender shows burn marks ! , shows we ride them hard i guess,
    Colin
     
  8. rvich

    rvich VIP MEMBER

    Joined:
    Jul 25, 2009
    Wait! What? On hard braking there is enough flex for the front mudguard to be pushed into the headers? Is this frame flex, fork tube flex or both? Sounds like a good reason not to upgrade the brake!
     
    Last edited: Oct 8, 2018
  9. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    No, it's due to later models having an increased radius front mudguard/fender to clear the later 4.10 section tyre.
     
  10. B+Bogus

    B+Bogus

    Joined:
    Jun 28, 2009
    I guess the foregoing explains why Norton put out a service bulletin instructing dealers to fix broken 'S' exhausts by replacing it with the Roadster system?
     
  11. DogT

    DogT VIP MEMBER

    Joined:
    Jan 20, 2009
    The S pipes were a 'style'. But the roadster pipes are infinitely more practical. Many times I wished I had the roadster ones.
     
  12. colin davie

    colin davie

    Joined:
    Jun 16, 2018
    Thanks all for input
     
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