Cracked Frame

Onder · Jul 23, 2023

Lot of energy expended in talking about this. Really, just order a new frame. Best answer when all is said and done. Nice that you can simply do it too.

baz · Jul 24, 2023

Onder said:
Lot of energy expended in talking about this. Really, just order a new frame. Best answer when all is said and done. Nice that you can simply do it too.

Blasphemy !

Ron Hulton · Jul 24, 2023

baz said:
Did you ask the owner what the ISOs were set at?

Supposedly they were set to factory spec .

baz · Jul 24, 2023

Ron Hulton said:
Supposedly they were set to factory spec .

Maybe some time in bikes 52 years they were set to zero!
I can't think of another reason it'd crack
My 750 commando frame was cracked and welded in a similar place but further down before my ownership over 30 years ago
I assumed it'd been from too tight ISOs

concours · Jul 24, 2023

Onder said:
Lot of energy expended in talking about this. Really, just order a new frame. Best answer when all is said and done. Nice that you can simply do it too.

I strongly disagree.

I never cease to be amazed by some peoples aversion to weld repair.

A "new" frame would bring a lot of other issues to attend to.

KiwiShane · Jul 24, 2023

Sloppy front mount ...

baz · Jul 24, 2023

concours said:
I strongly disagree.

I never cease to be amazed by some peoples aversion to weld repair.

A "new" frame would bring a lot of other issues to attend to.

I agree
It's only a mild steel commando frame
Basically a bit of gas barrel
Not titanium!
I'd be painting it by now if it were mine
And worrying about something else
Just my opinion

Fast Eddie · Jul 24, 2023

I can see both sides of the argument.

Of course, you guys who are pro welders would repair it, you’d be kinda daft not to!

But a layperson is in a different position, and if he doesn’t know any local tame welders, and if it ended up being a strip down and pro jig based repair, it may well be that a new frame might not be that much more expensive and would most likely be a lot quicker.

baz · Jul 24, 2023

Fast Eddie said:
I can see both sides of the argument.

Of course, you guys who are pro welders would repair it, you’d be kinda daft not to!

But a layperson is in a different position, and if he doesn’t know any local tame welders, and if it ended up being a strip down and pro jig based repair, it may well be that a new frame might not be that much more expensive and would most likely be a lot quicker.

Have you considered the human cost!
The carbon footprint of producing a brand new frame!
It's an ecological disaster in the making
Think of all the destitute roadside welders out there waiting in the hot sun for a 20 buck job like this to come along!!!

Onder · Jul 24, 2023

I too get the point. Megga years ago I had a 1971 BSA OIF welded up on the job site by a friendly welder. It never gave issue. But then I probably would not have known if it did.
Yes it is long money for that new frame plus paint but as FE says, you need to know a welder who knows and is willing and if he isn't a mate it will not be cheap.
The unpleasant topic of money is always involved. The money doesn't matter unless you don't have it. :-(

Edit: The welder was an immigrant with a beat up old truck with a sorry welder aboard and later grew into a local successful welding biz. I went to him for a job for my boss in about 1985 and he looked at the piece and said '25 dollars an inch' and handed it to an employee! Do the math for today's rate.....

baz · Jul 24, 2023

Onder said:
I too get the point. Megga years ago I had a 1971 BSA OIF welded up on the job site by a friendly welder. It never gave issue. But then I probably would not have known if it did.
Yes it is long money for that new frame plus paint but as FE says, you need to know a welder who knows and is willing and if he isn't a mate it will not be cheap.
The unpleasant topic of money is always involved. The money doesn't matter unless you don't have it.

I had an oif lightning
The dam thing split the tank twice
And the cylinder base flange cracked off on one corner
Both got welded up

Onder · Jul 24, 2023

They cracked where the swinging arm connected to the big backbone. Once that was welded it was fine. However the rear mudguard parted company just below the frame loop. The front guard broke at the stays. The head lamp stays also broke.
Seat cracked around the hinges.
By the last year I suspect BSA was just bolting together parts and tossing them out the door. Precious little quality control.

mdt-son · Jul 24, 2023

Fast Eddie said:
But a layperson is in a different position, and if he doesn’t know any local tame welders, and if it ended up being a strip down and pro jig based repair, it may well be that a new frame might not be that much more expensive and would most likely be a lot quicker.

Shipping expenses to Canada may tip the scales in favour of a repair job.

- Knut

concours · Jul 24, 2023

"They cracked where the swinging arm connected to the big backbone. "

I did a few of these. 7014, with an AC buzz-box, with the bike upright.

Two are in my inner circle, still working fine 40 years later

acotrel · Jul 24, 2023

Fast Eddie said:
I can see both sides of the argument.

Of course, you guys who are pro welders would repair it, you’d be kinda daft not to!

But a layperson is in a different position, and if he doesn’t know any local tame welders, and if it ended up being a strip down and pro jig based repair, it may well be that a new frame might not be that much more expensive and would most likely be a lot quicker.

A new frame would be replacing dud with dud. - Better to improve what you have. Strip it down and get it into a jig. If you cannot find a jig, a simple one is easy to make out of a piece of channel and some scrap. I have one in my shed which I made for one of my projects. Wherever you are, there is usually somebody who can make and repair motorcycle frames. For me, I would have to drive 100 Km, but I would start at the local raceway. People still make push-bike frames for racing - shop around.
That fracture in the frame tube has started where there is a stress-raiser - you need to extend the ISO mounts a bit past that pont, or the frame will break again.
I am not a trades'-person - I am a scientist. I still have no trouble getting anything made or repaired. In the old days it was easy - even now, it is not too difficult.

Shelby-Right · Jul 24, 2023

Fast Eddie said:
I can see both sides of the argument.

Of course, you guys who are pro welders would repair it, you’d be kinda daft not to!

But a layperson is in a different position, and if he doesn’t know any local tame welders, and if it ended up being a strip down and pro jig based repair, it may well be that a new frame might not be that much more expensive and would most likely be a lot quicker.

ADVICE , To get hold of a good welder in your area , you need to go to a place that makes winery tanks , or stainless work etc , a sheet metal welder , there is always a pro welder there , other wise a shop that makes custom chassis or suspension components , TIG welder , I'd imagine if that frame was preped for painting it would have no mill scale , if it does after paint stripping use 9 % vinegar on a soaked rag , you don't want mill scale as it contaminates the weld and sort of undercuts the edges , need to make good access . Cheers

Fast Eddie · Jul 24, 2023

acotrel said:
A new frame would be replacing dud with dud. - Better to improve what you have. Strip it down and get it into a jig. If you cannot find a jig, a simple one is easy to make out of a piece of channel and some scrap. I have one in my shed which I made for one of my projects. Wherever you are, there is usually somebody who can make and repair motorcycle frames. For me, I would have to drive 100 Km, but I would start at the local raceway. People still make push-bike frames for racing - shop around.
That fracture in the frame tube has started where there is a stress-raiser - you need to extend the ISO mounts a bit past that pont, or the frame will break again.
I am not a trades'-person - I am a scientist. I still have no trouble getting anything made or repaired. In the old days it was easy - even now, it is not too difficult.

I disagree.

As far as I know, this is not a common failure mode on Commando frames Al.

So it is not an inherent stress riser in the design that is the root cause of this at all.

KiwiShane · Jul 24, 2023

The silver coloured frame is deffiently good for spotting cracks.

..I look forward the linishing/grinding starting to identify the extent of the repair....photos please

Ron Hulton · Jul 24, 2023

KiwiShane said:
The silver coloured frame is deffiently good for spotting cracks...I look forward the linishing/grinding starting to identify the extent of the repair....photos please

I'm not sure what route he will go but i will try to keep the information updated ..

CanukNortonNut · Jul 24, 2023

Get it down to the frame. Sandblast area, then reweld it with a good TIG weld shop. Work on Upgraded parts while your at it. Head steady, Mk3 Iso. Swingarm upgrades etc. etc. I would go with a engine oil filter upgrade as well.
IMHO.

Cracked Frame

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