E: Engine Exhaust Problem

Hitthebongos

Forum User
Non-VOC Member
Hoping someone can help , my new to me series C Comet desperately needs a new exhaust and silencer as
it has an old original battered Burgess with a pitted pipe , I removed the exhaust and silencer and found I
have a screw in exhaust pipe stud in the head where it should have been the bronze nut , soaked it and cannot get it
to unscrew from head so looks like I am stuck with it , exhaust stub measures 38 mm across so a standard exhaust from club spares
or Armours etc wont fit over or in length , has anyone else come across this or know what I could do apart from sticking the battered one back on ?
Thanks
Andy
 

Hitthebongos

Forum User
Non-VOC Member
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ClassicBiker

Well Known and Active Forum User
VOC Member
Hello Andy,
If you look Forty Years On, there is reference to exhaust port adapters, it can also be found here on the forum,
I would suggest that some previous owner did not like the idea of screwing in and out the exhaust nut so built the adapter or damaged the threads at some point in time and made the adapter.
Steven
 

BigEd

Well Known and Active Forum User
VOC Member
VOC Forum Moderator
Hoping someone can help , my new to me series C Comet desperately needs a new exhaust and silencer as
it has an old original battered Burgess with a pitted pipe , I removed the exhaust and silencer and found I
have a screw in exhaust pipe stud in the head where it should have been the bronze nut , soaked it and cannot get it
to unscrew from head so looks like I am stuck with it , exhaust stub measures 38 mm across so a standard exhaust from club spares
or Armours etc wont fit over or in length , has anyone else come across this or know what I could do apart from sticking the battered one back on ?
Thanks
Andy
I think the standard pipe is 1⅝" in old money, 1.625". 38mm is 1.496" So a standard pipe with the flange cut off might slide over the stub, maybe with a bit of packing. Preferable though to spend some more time trying to get the stub out, maybe using some careful heat around that area of the head.
 

Bill Thomas

Well Known and Active Forum User
VOC Member
Thanks Andy, Any spring fittings like some race people fitted ?,
Or just a clamp. Funny I had some pipes that didn't fit , Years ago,
And the back one I brazed a short pipe into the standard nut. With a fitting like that

Can you tell us the outside size of that fitting ?. Cheers Bill.
I think I might leave that in there, It was done for a reason ?,
The standard fitting has given a lot of people trouble over the years.
 
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Hitthebongos

Forum User
Non-VOC Member
Thanks for help everyone , there is just a finned clamp with a tightening bolt , amazing really it stood for 7 years and started 2nd kick on old fuel , cleaned tank out and carb , renewed fuel lines etc , Bill widest part of the fitting is 58mm with the stub being 38mm , mate suggested phoning Armours to see if they can make one to fit
 

Bill Thomas

Well Known and Active Forum User
VOC Member
The inside of a Standard Comet pipe is as Ed says a nats under 1.1/2" or 38mm ish.
It makes sense that is the outside size of your fitting ?.
I would think you only have to take a few inches off the top of you new Armours pipe for it to fit ?.
If you asked Armours to make a special, It would be hard for them to know the sweep of the top bend ??.
If you did fit it like the old one, I think I would add a loose clamp about 12 " down from the top, To give extra support, We don't want it dropping down !.
If this worked maybe cut a few slots in the top of your new pipe to help clamp it ?.
 

Hitthebongos

Forum User
Non-VOC Member
Thanks Bill , I know I am acting like an old lady flapping about , it just threw me that fitting , I am going to buy an exhaust and silencer from Armours tomorrow , I am going to ask them to just take 3/4 of an inch off top for me and that should take into account how much would have gone into head and edge of stub . Thanks everyone
 
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