Rear loop issue

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fendermanz

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Nov 13, 2023
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Hi guys, been slowly trying to put this 72 Norton together after powdercoat and assembly realized the rear loop should be longer. This is my first Norton, already repaired some holes in frame. What options do I have , need to either keep it and cutomize the back or cut off the loop and reweld proper size? Damn howd i miss that 😔 no wonder seat looks strange. Maybe mske it cafe with a tail fairing? Hmm
photos.app.goo.gl

New item by Garrett R

photos.app.goo.gl photos.app.goo.gl
 
It is not only too short, it’s significantly at the wrong angle.

What to do largely depends on your plans for the bike I guess.

But IMHO I can’t work out what kind of seat arrangement would look good on that. I’d bite the bullet now and fix it.
 
fendermanz said:
Hi guys, been slowly trying to put this 72 Norton together after powdercoat and assembly realized the rear loop should be longer. This is my first Norton, already repaired some holes in frame. What options do I have , need to either keep it and cutomize the back or cut off the loop and reweld proper size? Damn howd i miss that 😔 no wonder seat looks strange. Maybe mske it cafe with a tail fairing? Hmm
photos.app.goo.gl

New item by Garrett R

photos.app.goo.gl photos.app.goo.gl
Click to expand...
You can sand and respray the back loop and weld in two pack , it'll all disappear under the seat .
 
Cut that wrong hoop off the frame at the last point it is the correct angle. (ignore the red lines and arrows, that is to explain where the frame bends in a front end collision)

Rear loop issue



Buy the hoop FE has the link and cut it back at the front to match the bit left on the frame.

Find two short lengths of tube that fit inside the tube of the hoop and have these partially inserted and welded into the hoop ends on the frame and then get the new hoop welded onto the frame over the ends of the tubes inside the frame hoop.

Then get these support pieces welded on the inside of the hoop for extra support.

andover-norton.co.uk

Andover Norton - FRAME REAR SUSPENSION MOUNT PLATE (Mk2) - 06.4282

FRAME REAR SUSPENSION MOUNT PLATE (Mk2)
andover-norton.co.uk

and these on the outside

andover-norton.co.uk

Andover Norton - FRAME REAR SUSPENSION OUTER BRACKET - 06.0412

FRAME REAR SUSPENSION OUTER BRACKET
andover-norton.co.uk
 
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Both the length and angle must be right for the rear fender to fit and be right and if the rear fender is not right, then the taillight will not sit right. Can you tell where it was cut? If at the front, it may be difficult to put the replacement rear loop in place - no telling how it was done - may already have a tube inside od the tube.

Frames and parts bikes become available relatively often. There are two frames on eBay right now. One is a decent looking 850 frame so it already has the reinforced rear loop. Changing the frame is an added expense to be sure, but might be worth considering.
 
The picture you posted is a small thumb nail so little detail can be seen, post a larger picture and I can mark it to show where to cut. It looks like you can cut just after the shock mounting plates and use 80% of the Andover Norton Hoop, the inner extended gusset shock mount plates from AN are thin enough to be welded over the current short plates giving extra thickness. The frame is plain low carbon steel that any competent welder can weld but get someone experienced with welding frames ie using generous chamfers at joints for deep penetration welds which are the strongest but not seen once dressed.
 
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kommando said:
The picture you posted is a small thumb nail so little detail can be seen, post a larger picture and I can mark it to show where to cut. I looks like you can cut just after the shock mounting plates and use 80% of the Andover Norton Hoop, the inner extended gusset shock mount plates from AN are thin enough to be welded over the current short plates giving extra thickness. The frame is plain low carbon steel that any competent welder can weld but get someone experienced with welding frames ie using generous chamfers at joints for deep penetration welds which are the strongest but not seen once dressed.
Click to expand...
Can't really be sure, but in the picture it looks like the existing loop it at an angle higher than original. If so, your idea won't work. As you said, a much bigger picture would help.
 
Fendermanz, don't beat yourself up too much.
I have heard many stories over the years from guys who had parts painted, powder coated, and plated that were missing brackets, needed reshaping, and other modifications after the fact. Happens to the best of them.
 
kommando said:
Find two short lengths of tube that fit inside the tube of the hoop and have these partially inserted and welded into the hoop ends on the frame and then get the new hoop welded onto the frame over the ends of the tubes inside the frame hoop.
Click to expand...
The original loop needs to be trimmed forward of the bogus welds, aft of the rear frame bracing plate (061973). You may be able to salvage the gusset plates, however fitting Mk3 gusset plates will give the new loop more support. Shorten the new loop to match this location.
Have short overlap tube stubs made (approx. 6*d long) which fit snugly inside the existing and the new tube. Tack or braze weld the overlap tubes into the remnants of the existing loop (allow 3*d to protrude). Install the prepared new loop section, allowing a small gap. Tack weld new tube section to the overlap tube stubs. Have angle and length measurements taken by a good frame to make sure the new loop is in the correct position wrt. length and angle before finalizing the fillet welds, joining the new loop section to the remnants of the existing tube and the overlap tube by butt welds. Lastly, weld (new or existing) gusset plates to the new loop by fillet welds. Good luck!

- Knut

Corrected for the correct term "tack welding"
 
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Not sure what your plan is, Kenny Dreer used to shorten that loop for his tail sections.
www.bike-urious.com

1973 Kenny Dreer Norton VR880

Kenny Dreer, the man who almost brought Norton back from the grave several years ago, got his start restoring motorcycles from the British marque at his shop called Vintage Rebuilds (VR) near Portl…
www.bike-urious.com

Not sure about the angle, but it did angle up to support the tail section.
Can't find it, there is a picture of one with the tail section removed and all the electrics back there.
I did find this, looks like the loop is angling up behind the shock.

Myself, I wouldn't be in a hurry to cut it off.
 
DougC said:
Not too clear on the photo, but it looks like the front tank and coil mounting support bracket may have been modified.
Click to expand...
Are the front fuel tank mountings in place?

Rear loop issue


Also, the lower frame gussets have addtional drillings in them, either for weights savings or rear mountings.
Where did this frame come from.
Me thinks it was set up as a Cafe Racer or Racer or least started a build at one time.....
 
marshg246 said:
Both the length and angle must be right for the rear fender to fit and be right and if the rear fender is not right, then the taillight will not sit right. Can you tell where it was cut? If at the front, it may be difficult to put the replacement rear loop in place - no telling how it was done - may already have a tube inside od the tube.

Frames and parts bikes become available relatively often. There are two frames on eBay right now. One is a decent looking 850 frame so it already has the reinforced rear loop. Changing the frame is an added expense to be sure, but might be worth considering.
Click to expand...
Thanks for your input. I saw the 850 and theres a 750 as well. My bad as I thought tge angle was normal lol ugggh. I have a welder.
MichaelB said:
Are the front fuel tank mountings in place?

Rear loop issue


Also, the lower frame gussets have addtional drillings in them, either for weights savings or rear mountings.
Where did this frame come from.
Me thinks it was set up as a Cafe Racer or Racer or least started a build at one time.....
Click to expand...
There were alot of issues with the frame at first, I wish I knew, prev owner didnt know much. Ive already welded the kickstand lug on this one. I dont mind making it a cafe racer if i could utilize what i currently jave. Not sure how to work the angle. I now realuize after trying to mount the seat something wasnt right, it shoukd be parallell with the frame (loop) and longer. Thanks for everyones feedback. I was wo deeing if i cut off tge loop and welded tge tube after the main frame ends would tgat be safe. I have a mig/tig. Im okay with a cafe racer jyst not sure how to make a seat rear cowling/fender work. Thought maybe someone here has seen this before. 🤔
 

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