1974 Commando frame issue

baz said:
Have you seen the size of the top tube 'spine' on a commando frame?
Click to expand...
Wasco in the states is the only place I know, Richard is super knowledgeable with Commando frames

www.wascoframe.com

Wasco Frame Service

Motorcycle frame straightening and repair. Knuckehead, Panhead and Shovelhead restoration.
www.wascoframe.com www.wascoframe.com
 
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My 74 850 came to me with very similar down tube bends and conpressed areas. Presume highway or crash bars fitting at some point. I rode bike for many yrs, some 15k miles put on it under my ownership, never any issues. But it did always linger in back of my mind. When engine out work was done, i had the shop send it to a local frame guy who repaired the bends via cut/insertion of straight tubes/rewelding...and he put it on a commando frame jig to confirm all correct.
I believe Norman Whites restoration book describes how to deal with frame damage in this same way.
 
No throw it away and convert it to a Featherbed frame lol, no i have seen worse that that on frames and have straighten a few a British bike frames using home made jigs tie downs and a few car jacks and lumps of wood, best to straighten without using heat and stretching the frame a little over so the steel springs back, you might have to do it a few times to get it right.

Ash
 
concours said:
A lot of this material has been covered. A quick search here on the forum. Will let you read and look at pictures for half the day.
Click to expand...

Will a search on the forum tell me if there is a lot of strain at the isolastic mount on the OPs Commando??

If there was a lot of strain there it may indicate a significantly bent frame.
 
TJBaker57 said:
Will a search on the forum tell me if there is a lot of strain at the isolastic mount on the OPs Commando??

If there was a lot of strain there it may indicate a significantly bent frame.
Click to expand...
Sorry, I read that one quickly and I thought it was the OP saying he had binding. My mistake.
 
TJBaker57 said:
Will a search on the forum tell me if there is a lot of strain at the isolastic mount on the OPs Commando??

If there was a lot of strain there it may indicate a significantly bent frame.
Click to expand...
A "significantly bent frame" would be visible to the naked eye, and may call for a frame replacement.
I think some deformation could be absorbed by the rubber mounts - compression of rubbers is not a good measure for state of the frame.
The workshop manual has pictures with frame checking dimensions. I would go by them.

- Knut
 
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mdt-son said:
A "significantly bent frame" would be visible to the naked eye, and may call for a frame replacement.
I think some deformation could be absorbed by the rubber mounts - compression of rubbers is not a good measure of state of the frame.
The workshop manual has pictures with frame checking dimensions. I would go by them.

- Knut
Click to expand...

I will try to explain what I was thinking.

In the manual the dimensions given for the distance between the front and rear isolastic mounting holes is 18.28".

Lets say as you are removing one of those isolastic mounting bolts that sucker is just stuck in there. As you finally force it out there is a bit of a clunk. You can see that there is no way you are getting that bolt back in that hole as it just doesn't line up. To me that would indicate perhaps that 18.28" specification is no longer met in this frame, perhaps due to the bends above the front isolastic mounting point.
 
TJBaker57 said:
I will try to explain what I was thinking.

In the manual the dimensions given for the distance between the front and rear isolastic mounting holes is 18.28".

Lets say as you are removing one of those isolastic mounting bolts that sucker is just stuck in there. As you finally force it out there is a bit of a clunk. You can see that there is no way you are getting that bolt back in that hole as it just doesn't line up. To me that would indicate perhaps that 18.28" specification is no longer met in this frame, perhaps due to the bends above the front isolastic mounting point.
Click to expand...
Just bash the fu cker in, she be right lol
 
ashman said:
Just bash the fu cker in, she be right lol
Click to expand...
I have a 73 850 frame with light crushing to both front tubes from a P.O. crash bar fitting . No bendings . I'm thinking filler will do it and repainting . History was "The Jumper " from Movie Production days . I worked in Movie Production for 6 years . Canada .
 

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