1968 frames

MarkT · Dec 14, 2015

I spontaneously purchased a 68 Commando from Ebay the other day and realised once I got it home it has an original 1968 frame unmodified uggghhh. It has been beautifully restored using 98% NOS. Somehow this frame (128542) has slipped through the cracks (pun intended). The frame looks perfect.

I have read a lot of material about these frames and was wondering if in reality it is WHEN not IF the frame will crack scenario. I do want to ride this bike occasionally.

Can anyone show a pic or drawing of strengthening modifications they have done or recommend doing to these frames to make them safe.

Mark

pierodn · Dec 14, 2015

http://www.andover-norton.co.uk/FRAME%2 ... 0Parts.pdf

They sell the update for your early frame (called Widow Maker).
You need 767154, 061334, 061240, 061241 to make the frame safe.
You will solve the possible crack of the FRAME MAIN TOP TUBE.
Ciao
Piero

acotrel · Dec 14, 2015

Many years ago I looked at a commando frame with a view to building a second race bike. I couldn't come at it. However the other options seem to be few and far between. Here in Australia we can buy replica featherbed frames for about $3000. I also asked Barbour Engineering at Attleborough about a second Seeley frame. It all seems too expensive. These days I'm looking for a decent BSA A10 frame. When combined with the fork yokes off an early 60s 650 Triumph, they handle extremely well.
I'd be interested in getting suggestions about other options.

Paddy_SP · Dec 14, 2015

I'm currently restoring a 1968 frame that had snapped twice - once in the usual place, and then again right next to the badly-applied reinforcement. It's a very close frame number to yours - 128017. My solution is to sleeve the inside of the top tube with a length of seamless, and then replace the piece of the spine that I had to cut out - again with seamless. Likewise, I'm replacing the front downtubes with more CDS. The idea is for it to look original but still be safe - albeit that this is specifically intended to be a museum piece rather than a rider.

cjandme · Dec 14, 2015

MarkT said:
......... and was wondering if in reality it is WHEN not IF the frame will crack scenario. I do want to ride this bike occasionally........Mark

I would submit that it is a matter of when and not if. It would be a shame to damage the frame on one of the occasional rides. as it stands now there is only the triangulation modification to be done. If it lets go during one of the occasional rides than you'll have to contend with the repair and possible straightening to be done along with the modification. You're ahead of the game the way I see it.

MarkT · Dec 14, 2015

pierodn said:
http://www.andover-norton.co.uk/FRAME%20COMMANDO%20PART%2006.1130%20Component%20Parts.pdf

They sell the update for your early frame (called Widow Maker).
You need 767154, 061334, 061240, 061241 to make the frame safe.
You will solve the possible crack of the FRAME MAIN TOP TUBE.
Ciao
Piero

That's what I was after...thanks Piero.

MarkT · Dec 14, 2015

Thanks so far for your ideas and help. It's not going to be be the disaster I thought it might be after all.

Mark

Dean · Dec 14, 2015

Hi Mark

My 68 is 128372 so very close to yours. Mine also came with original frame. I bought the tank mounts from Andover as was stated earlier but to save a bit of money on postage used a piece of locally purchased 1"tube and made up the lower spine strenthening piece myself.

I would recommend you look at the down tubes closely. My R/H tube was cracked about 1.5"below where it attaches to the headstock. Top tube hadn't cracked.

It's not a hard job and you could probably do it with the bike still assembled although my is a full resto.
Also repaired the rear loop where PO had cut it and bashed in a piece of solid bar, then made up new shock top mount to support the rear loop better.

Cheers
Dean

Tintin · Dec 15, 2015

pierodn said:
They sell the update for your early frame (called Widow Maker).

The PDF shows 06-1130 and contains the bits and pieces needed to repair this frame. The widowmaker is 06-0406. My widowmaker was despatched in August 1968 and I had a chat with Joe about this subject, the drawing for 06-1130 is from as early as Oct 1968. AFAIK there is no factory drawing which shows the rework of 06-0406.

You need 767154, 061334, 061240, 061241 to make the frame safe.

No, all that is needed is the horizontal tube and it will not fit directly because the head stead mount is different. My 1968 frame was modified sometime in the past. It retains the original coil bracket which is welded to the down tubes, the gusset is still on there and the reinforcement tube has been pushed between and welded to the two small brackets of the orginal HS mount. Also the tube which was used on my frame is slightly smaller. All in all it is still very much different to the later frames.

BTW, I remember that Joe mentioned the AN fastback still has an unmodified 06-0406 frame and is still occasionally used so maybe it is not that much of a problem. Plus there are new frames available, 06-1130 is in the list for GBP865.

Tim

MarkT · Dec 15, 2015

Dean, thanks heaps for posting the pics. Makes it very clear what has to be done. Tim, that's excellent news. I might email Joe and get his view on riding this old girl occasionally and determine what the risks might be from his perspective with an unmodified frame.

It's a real shame someone has gone to a lot of time and money to restore this without making the frame mods.

Mark

oleblu72 · Dec 15, 2015

MarkT said:
I spontaneously purchased a 68 Commando from Ebay the other day and realised once I got it home it has an original 1968 frame unmodified uggghhh. It has been beautifully restored using 98% NOS. Somehow this frame (128542) has slipped through the cracks (pun intended). The frame looks perfect.

I have read a lot of material about these frames and was wondering if in reality it is WHEN not IF the frame will crack scenario. I do want to ride this bike occasionally.

Can anyone show a pic or drawing of strengthening modifications they have done or recommend doing to these frames to make them safe.

Mark

Hi Mark I bought my 68 about 21 years ago the title says its a 69 but the serial # 128231 says its a 68. She's just been sitting in the garage never started it or rode it ( I know why not ). I've never pulled the fuel tank off her but as far as I can tell it still has the old head stock gusset so I don't know if it has any cracks or not but from what I can see it doesn't look like it. Its all original and the speedo says it has around 4000 miles but we know how those work, but one of these days I have to get busy and get her running. I have another Fastback that's a 69 but it doesn't have the original motor anymore. It has a strange looking fuel tank it looks like a Fastback tank but it has side extensions on it that stick out about 1/1/2 inchs and it follows the contours of the tank it doesn't look like a home made deal. I've enquired about the tank before but have found out nothing, I've read that Norton use to offer custom goodies but other than Dunstal that's all I know about.

Mark

MarkT · Dec 16, 2015

I pulled the tank yesterday and had a real close look in good light and I could see and feel there had been tamperings behind the gusset and on the downtubes. I contacted the PO and he said he had inserts placed in these areas and the frame would be "right". Hmmmm. It is a very tidy job I must admit though.

Additionally, I spoke to Joe at Andover and his view is the problem may not have been as prominent as reported as he has an original framed bike that he rides without issue and has done for some time.

Mark

Dean · Dec 16, 2015

Hi Mark

Here's a couple more pics from after I had welded on the tank/coil mounts. These were the two pieces I got from AN.

Paddy_SP · Dec 17, 2015

Dean - good job - well done!

MarkT - I read somewhere (was it in an article by Mike Jackson?) that the primary cause of the early frames snapping was because the crates they were delivered in were simply pushed off the back of the truck as they didn't have a fork lift - the resultant drop was the shock that started the cracking process. I don't know which bikes this applied to though, but one has to assume that a bike that wasn't dropped has a lesser chance of problems!

MarkT · Dec 17, 2015

Dean
That is a very nice job. I think for now I will take a punt and just enjoy it every now and again.

Paddy
That would have been an interesting read. Fell off the back of a truck...I guess the theory has some merit particularly if they had to straighten them cold or something??

Mark

L.A.B. · Dec 17, 2015

MarkT said:
Fell off the back of a truck...I guess the theory has some merit particularly if they had to straighten them cold or something??

The frame failures were certainly attributed to the impact loading from the crate handling. As far as I know, no attempt was made to straighten frames because nobody was aware there was a problem until the frames began to break.

NORTON COMMANDO 1968 STRUCTURE:FRAME AND MEMBERS Recall NHTSA Campaign ID Number: 74V239000 | Justia

View recall details for the 1968 NORTON COMMANDO with NHTSA campaign number 74V239000. Stay informed about safety issues affecting your vehicle. Ensure the safety and reliability of your NORTON COMMANDO.

auto-recalls.justia.com

Possibility that the large diameter top tube of the main frame,may fracture in service due to unusual conditions of use following an induced weakness initiated by unsatisfactory crating and warehousing procedures. (corrective action, on machines affected, within the series of engine numbers 126125 to 128634, the frame should be changed in accordance with the instructions given in the 750cc model workshop manual (part no. 063419)

Ken Sprayson gives a brief account of this and how the problem was corrected (by adding the 1.0 inch diameter bracing tube and relocating the fuel tank brackets) in his book: 'The Frame Man'.

norbsa48503 said:

Fast Eddie · Dec 17, 2015

Wow!

That picture would be enough to persuade me to NOT ride an early frame un-modified.

The theories about induced weakness from unsatisfactory crating may well have been true at the time.

But that is interesting history. The real question, 48 years later (if you are considering using one) is what about the induced weakness of 48 years of fatigue and unknown history of any potential 'induced weakness' incidents?

Doesn't seem worth the risk IMHO.

kommando · Dec 18, 2015

Even if your bike was unloaded correctly, how many times has it been driven up a kerb which must have a similar effect.

Dean · Dec 18, 2015

If I was going to leave the frame unmodified I would be inspecting it before each ride. A strong light and a 10x magnifying glass should be enough. In my case the r/h down tube was cracked and all else was ok. The crack was about half way around the tube on the outside of the r/h tube running front to back. I stripped off the paint and did a crack test with a red dye penetrant crack test kit.

If it isn't cracked now and your not going to give it a daily thrashing it should be ok but I would definatly keep an eye on it.

Cheers
D

Gemini 3 · Mar 24, 2017

Hi,hope I am not resurrecting too old a post.
I have a '68 unmodified frame rider that showed no signs of fatigue. I went for a 116 mile ride last weekend on motorway and hilly, twisty roads and the bike was running well and handling fine.
I stopped at our lunch destination and the front end almost fell off. The frame was almost identical to the picture earlier in this post with 3/4" of backbone still intact.
Entirely fixable but I count myself very lucky and am now of the opinion that it is when not if.

Cheers, Mike.

1968 frames

MarkT

pierodn

acotrel

Paddy_SP

cjandme

MarkT

MarkT

Dean

Attachments

Tintin

MarkT

oleblu72

MarkT

Dean

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Paddy_SP

MarkT

L.A.B.

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NORTON COMMANDO 1968 STRUCTURE:FRAME AND MEMBERS Recall NHTSA Campaign ID Number: 74V239000 | Justia

Fast Eddie

kommando

Dean

Gemini 3

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