850 Exhaust Headers

M

Michael R

Joined
Mar 6, 2016
Messages
3
I have observed with my recently acquired 1974 Norton 850 Commnando Roadster that the exhaust tips are uneven when viewing them from behind. That is to say, one exhaust tip is higher that the other, and is an unequal distance from the wheel than the opposing exhaust tip. As I understand it, this is a common problem and can be blamed on the exhaust header manufacturer. My question to the group is this:

Is it true that uneven exhaust tips are generally caused by poorly made headers and if so, are there any suggestions on where to buy high quality headers that will eliminate this problem. I would value your opinions and as always, thank you in advance for your input.
 
Are your headers balanced? If they do not have the balance pipe it is probably a matter of twisting the pipe in its socket so that both sides match. There is a ton of info here on how to deal with tightening exhaust nuts. It is easy when torquing down the large exhaust nut to twist the pipe out of position. If you have a balance pipe, well, I would probably get new headers without it.

Russ
 
Many other things to do... that can help. Side plates move up, down, shim with washers, I cut 1/8" offthe threaded bosses on the mufflers, little steps add up
 
rvich said:
Are your headers balanced? If they do not have the balance pipe it is probably a matter of twisting the pipe in its socket so that both sides match.




Russ
Click to expand...

,,,,or are they individual pipe replacements? If replacements, are you using the conical seat/split collet arrangement that was originally used when the balanced pipes were introduced? Balanced or not makes no difference to me but I find the conical seat/split collet design introduced with them ads a lot more adjustability than the single plane gasket and flanged pipe does. The individual pipes can pivot around an axis while the gasket only arrangement can only rotate.
 
Your order of tightening up the whole system is in my notes : Hand tighten up both exhaust rosebuds (headnuts). Then the muffler clamps. Then the rubber muffler mounts (no strain on the rubbers and not crooked). Do this whilst on the 2 wheels , not on centerstand. I use copper high heat silicone in exh. threads , the troublesome 850 crossover joints and at the muffler -to- pipe fit. Then proper tool tighten up the rosebuds , drive , come back home and retighten hot. Hope this helps your alignment concerns. :)
 
Biscuit said:
If replacements, are you using the conical seat/split collet arrangement that was originally used when the balanced pipes were introduced?
Click to expand...

The balanced pipes were fitted from '73, but spherical seatings/flared pipes didn't appear until the 850 Mk3 ('75).
 
They are shown in the Mk 3 parts books.

This is the spherical seat, that goes into the exhaust port.
The pipe has a flared end, with a similar spherical shape, so it can settle into a position of best fit...

850 Exhaust Headers
 
Sorry Rohan :oops:
I was referring to Michael R to show a picture of his bike and the issues with his headers. If he can show the pipes as they exit the head and how they hang without the pea shooters on. Sometimes a bike may have been sold with two different halves attached from different manufacturers. You don't really notice it until you take it apart or examine it more closely. I for one know this. I have one PR down tube set aside if and when I find one to match the other half. :D I would also check that the frame is not bent by taking the tank off and examining the main tube for a bend or the front down tubes ahead of the engine. The commando frame is very light and it doesn't take much to tweak it out of shape.
cheers,
Thomas
CNN
 
rvich said:
Are your headers balanced? If they do not have the balance pipe it is probably a matter of twisting the pipe in its socket so that both sides match. There is a ton of info here on how to deal with tightening exhaust nuts. It is easy when torquing down the large exhaust nut to twist the pipe out of position. If you have a balance pipe, well, I would probably get new headers without it.

Russ
Click to expand...

I have a 750 that the kickstart is hitting since I put new headpipes on. If I loosen the headpipe to align it do I have to replace the seal or will it tighten up and seal again.
I think it just needs a twist.
 
L.A.B. said:
Biscuit said:
If replacements, are you using the conical seat/split collet arrangement that was originally used when the balanced pipes were introduced?
Click to expand...

The balanced pipes were fitted from '73, but spherical seatings/flared pipes didn't appear until the 850 Mk3 ('75).
Click to expand...

Ha, did not really know that. For some reason thought all balanced piped 850's had the conical seats. Off topic I know, but think it would be a real nightmare to fit a new balanced system utilizing other than the MK3 system. Now wonder so many opt out.
 
My '74 has never been right. The right side has always been droopy by about 3/4", which annoys me to no end. Maybe it's the left that's high... I have had the entire balance-piped system off (for other reasons), and am unable to make the pipes line up without putting things into a horrendous bind. It's just where the stupid thing naturally lays. Never had any interference with the kickstart. I'll take the lop-sided look over broken header pipes any day, thank you...

Biscuit said:
...it would be a real nightmare to fit a new balanced system utilizing other than the MK3 system.
Click to expand...
It is...

Nathan
 
There are detailed instructions for picture posting up the top of this forum - 3rd listing down.

Basically, you upload your pics to one of the free pic hosting places (photobucket etc),
and then put the link here and use the button to make it display.
hopethishelps.
 
I had this same problem about this time last year. I received a brand new set of AN headers from Old Britts. It didn't matter how or what I did, they just never lined up. Fred at Old Britts reordered me a new set and guess what? They didn't line up either. I sent them back to Old Britts and Fred tried fitting them on his bike. They also didn't line up for him. He ordered me another set from a different manufacturer and the chrome was so poor that he didn't even forward them to me. Oh yeah, three months had now elapsed. I then decided to bite the bullet and go big dollar wise and get a set from Viking Exhaust. Fortunately the US dollar was very strong and that helped to ease the pain. The owner ,Paul, was a pleasure to deal with. He explained the build process and kept me informed throughout. They fit perfectly. Paul hand bends these units and checks the fit before sending them off to the chrome shop. I notice that Old Britts carries Viking again. Fred probably got fed up with the fit issues. Good luck!
 

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