Please help me identify my frame

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So I drilled off the serial plate, now knowing that the rivets are non-original, and hoping to find a serial number stamped underneath. Nothing. Then I carefully checked the inner shock plates, as LAB suggested, and came up with a disappointment: it appears that the longer plates have been added to the original--beautifully done, I might add. All this seems to point to a 750 frame--but it does have the wider loop at the rear.

That obviously begs the question: if I have a 750 frame with the correct yokes, but everything else is 850, does that matter--apart from its lack of originality? Are there any safety/riding issues.

Sometimes ignorance is bliss :(
 
Nielsen said:
That obviously begs the question: if I have a 750 frame with the correct yokes, but everything else is 850, does that matter--apart from its lack of originality? Are there any safety/riding issues.
Click to expand...

None that I can think of.
 
L.A.B. said:
Nielsen said:
That obviously begs the question: if I have a 750 frame with the correct yokes, but everything else is 850, does that matter--apart from its lack of originality? Are there any safety/riding issues.
Click to expand...

None that I can think of.
Click to expand...
That's a relief, though I guess my 'original' bike is a 'bitsa'. Not very happy about that! Not that I was scammed. The previous owner died in about 2005 and I bought the bike from his widow after it had sat for about 8 years. She didn't know......
 
Nielsen,
If this bike could only talk. :?: :?: :?: Detective work at play. We are starting to see a pattern of key points coming to light.
It looks like the frame was switched out at sometime in its past. As others have already commented the rivets are hammer type. Walridge carries the plates and the rivets 061287 and an ID plate 063247 for your year bike. I would imagine the frame rivets were ground off and re-drilled hence the incorrect location of your number plate. I bet if you look inside where the head bearings are ( if you remove them along with the spacer) you will see the original rivets still in the factory location. These are hard and tough to drill out so that is my educated guess. Good luck with finding the 850 upper and lower yoke. Take the tank off and inspect the big spine tube for any bow. Go to the back of the bike and look down the spine and view the rear wheel centre line. This should be very close. Carry on.
Cheers,
Thomas
CNN
 
Thanks for that, Thomas. Rivets ordered from Walridge! Now that I think my 850 has a 750 frame, the good news is that the yokes are the right ones! To be honest, however, I would rather have had the wrong yokes and the matching numbers frame. Sometimes one should perhaps leave well enough alone, but I love a sleuthing project--despite it coming back to haunt me. I might as well take the head bearings and spacer out. My guess is that you are exactly right: there'll be traces of rivets inside.
 
Nielsen said:
I might as well take the head bearings and spacer out. My guess is that you are exactly right: there'll be traces of rivets inside.
Click to expand...

I took them out on my 72 when I replaced the frame. I had an accident with it in the early 80's and bent the frame and me "Two cracked ribs"
These rivets are a real bear to get out as they are a spiral taper. They look like this: https://www.google.ca/search?q=name+pla ... M4h_Fe8%3D
Cheers,
Thomas
CNN
 
Nielsen said:
Based upon Dave Comeau's comprehensive chart on frames (thanks for the link to atlanticgreen.com), the hoop width of mine is correct for March '74 (it's indeed 'wide). The serial plate on the front is canted to the right when viewed from in front of the bike (which means to the left if seated like a rider and viewing down on it). Comeau says it should be to the right. I'm going to write to him for clarification.

I put a straightedge on the frame tubes, and everything seems to be fine.

I'll check on that rear wheel spacer. I did spend a good deal of time measuring the wheel alignment and altered it a little since that photo was taken. I also shifted the fender to centre it better. The result is that the rear wheel appears to be properly centred now.
Click to expand...

All my website shows is only collected data... no right/wrong /left /right/up/down as correct or incorrect. Analysis is owed by you ! :?
 
Dynodave: of course I take full responsibility for any analysis and conclusions I've reached from consulting your excellent list of observations on Norton frames. I'm just really grateful for the community of experts out there, such as yourself, who are willing to help those of us still learning.
 
Final sanity check on your frame - the triangular gusset behind the LH Z-plate *should* have the date and/or year of manufacture stamped on.
From what I can tell, this only seems to apply to the later type (no centre stand bracket) frames - I have a couple of '72 frames which show month/year, and a '71 which reads (I think) RX 71. Could be KX 71.
Either way, it's some kind of confirmation!

It looks like a bit of those shock mount gussets need to be shaved off to restore sufficient shocker clearance - otherwise no problem.
 
Andy: Bingo. It's hard to see but the triangular gusset behind the left hand Z plate says what I think is "P372" which, following your logic, means the frame was made in March '72 [edited]. I hereby declare my remarkably original, numbers matching, '74 Norton Commando a bitsa made up of a '74 with a '72 frame. I wonder if that makes it a '73 :wink: thanks, everyone, for all your help with this. Disappointed as I am, at least I know what I've got.
 
Nielsen said:
Andy: Bingo. It's hard to see but the triangular gusset behind the left hand Z plate says what I think is "P372" which, following your logic, means the frame was made in February '73.
Click to expand...

How did you arrive at February '73 from "P372"? I think it is more likely to be R372 = Reynolds March '72.
frame-number-riddle-t8487.html
Davo said:
Please help me identify my frame

LH side Frame
Click to expand...
 
I read P372 as Mar 72 which would make it a 750 frame, will look at my 750 72 frame to see if it has the same markings.
 
Nielsen,
We are finally getting to see the frame number date of manufacture. Reviewing your first picture. It looks like the PO welded up those small gussets on the inboard side of the rear shock attachment making it to look like an 850 frame. It is probably a little out of dimension to stock, which is why I see the top of the shock contacting the gusset. I would keep the the yokes you have.
I have modified my gussets on a 72 as per OldBritts. http://www.oldbritts.com/38_200001.html :wink:
Keep us posted.
Cheers,
Thomas
 
I think judicious grinding with a grinder should have those inboard shock gussets cut back to the point where they both look 'correct' and don't contact the top of the shock. She's a wonderful old thing, despite her dubious pedigree.
 
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