Bent frame, still safe to ride? (2017)
- Thread starter NKN
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Re: Frame quiz
Easter Island statues.
Easter Island statues.
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Re: Frame quiz
Robert Mapplethorpe? Or, something's been clamped and grossly over-tightened to those frame tubes. I've got a kinda sorta supposed to be Norman Hyde oil cooler that clamps in that general area, but you'd have to work so hard with it to produce those marks I can't believe it's that. Something like it though, maybe? Over-tightening crash bar clamps could do that, as I recall back in the 70s and 80s they were both common and quite coarsely made.
Robert Mapplethorpe? Or, something's been clamped and grossly over-tightened to those frame tubes. I've got a kinda sorta supposed to be Norman Hyde oil cooler that clamps in that general area, but you'd have to work so hard with it to produce those marks I can't believe it's that. Something like it though, maybe? Over-tightening crash bar clamps could do that, as I recall back in the 70s and 80s they were both common and quite coarsely made.
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Re: Frame quiz
Damage from clamps used for highway foot rests.
or
Something getting terribly loose allowing a few fins of the cylinder head to ding the down tubes.
Damage from clamps used for highway foot rests.
or
Something getting terribly loose allowing a few fins of the cylinder head to ding the down tubes.
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Re: Frame quiz
An over tightened steering damper?
An over tightened steering damper?
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Re: Bent frame quiz
Yes Robert M. behind the bike. On the LH side there are some lower marks, so it's more like if it was something fixed to the frame like crash bars or highway foot rest.
Tought in the beginning that the bike had an accident an it was marks from a jig, when trying to pull back the frame.
Saying that because tubes are not that straight. Especially the RH side:
Is this common? Dangerous?
I tried with the old school string and everything is OK, even if it's hard to see on photos:
NortonMKIIA850 said:
Yes Robert M. behind the bike. On the LH side there are some lower marks, so it's more like if it was something fixed to the frame like crash bars or highway foot rest.
Tought in the beginning that the bike had an accident an it was marks from a jig, when trying to pull back the frame.
Saying that because tubes are not that straight. Especially the RH side:
Is this common? Dangerous?
I tried with the old school string and everything is OK, even if it's hard to see on photos:
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Re: Bent frame quiz
If, when you slide the front iso bolt in, it goes through without much distortion of the front iso rubber then I think you have not much to worry about. My frame always needed a lot of distortion of the front rubber and after 35 years I found that the the frame was parallelogramed to one side. Probably due to crash damage. All my drain plugs were wire locked and in a previous life the bike had been raced and crashed I'm sure.
If, when you slide the front iso bolt in, it goes through without much distortion of the front iso rubber then I think you have not much to worry about. My frame always needed a lot of distortion of the front rubber and after 35 years I found that the the frame was parallelogramed to one side. Probably due to crash damage. All my drain plugs were wire locked and in a previous life the bike had been raced and crashed I'm sure.
rvich
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Re: Bent frame
The the main tube on top straight? In an accident that bends back the front forks, it is likely the top tube will get humped. It doesn't precluded damage to lower tubes from other types of accidents but it is another bit of evidence.
Russ
The the main tube on top straight? In an accident that bends back the front forks, it is likely the top tube will get humped. It doesn't precluded damage to lower tubes from other types of accidents but it is another bit of evidence.
Russ
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Re: Bent frame quiz
No, it's not unusual for Commando spine tubes to curve slightly at that point.
If there's any damage to the spine tube it usually occurs in the area just behind the headstock.
NKN said:
Second photo doesn't want to upload. But it clearly shows that it's not straightened with the first part. Perhaps a frontal touch?
No, it's not unusual for Commando spine tubes to curve slightly at that point.
If there's any damage to the spine tube it usually occurs in the area just behind the headstock.
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I have a frame with exactly the same creasing. I've always wondered what caused it. Mostly assumed a sidecar mount bracket as mine also has a slightly flattened lower right frame rail (under the motor/gearbox). It is a USA import. The front ISO fitted but was tight. The frame,engine, swingarm, wheel assembly are currently in being checked by a frame straightener/engineer.
I wonder if this creasing will affect the strength of the downtubes as there is more tension than compression forces at this area?
I wonder if this creasing will affect the strength of the downtubes as there is more tension than compression forces at this area?
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In the US in the 70s I would assume hiway pegs or a Windjammer mounts over a sidecar.
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Steering damper mounts, Hiway pegs, crash bars, I think a sidecar most unlikely as the Commando frame is just not up to it. There was a seriously disabled chap who used to be seen at the IOM on an electric start with sidecar in the seventies but that's the only one I've ever seen.
rvich
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This topic has been discussed here before. Below is a link to one of those discussions. It is missing some of the photos but there is still some good information in it.
bent-frame-advice-requested-t5770.html?hilit=bent
Through some stroke of luck I was able to get the original photo of the damage from Photobucket.
Sadly I was not able to get Nortonspeed's photo of the proposed cross tube.
Note Ludwig's advice on the topic:
Frankdamp offered this in a different thread:
There are other threads that talk about adding a cross tube for stiffening the frame. I tend to think the damage in your photos is mostly cosmetic. But some research on the cross tube idea might be worth your time if it will help you have faith in the frame, particularly in view of Frank's comments should you want to upgrade your braking. I am sure there are current members here who have done this. I have not.
bent-frame-advice-requested-t5770.html?hilit=bent
Through some stroke of luck I was able to get the original photo of the damage from Photobucket.
Sadly I was not able to get Nortonspeed's photo of the proposed cross tube.
Note Ludwig's advice on the topic:
ludwig said:
Frankdamp offered this in a different thread:
frankdamp said:
There are other threads that talk about adding a cross tube for stiffening the frame. I tend to think the damage in your photos is mostly cosmetic. But some research on the cross tube idea might be worth your time if it will help you have faith in the frame, particularly in view of Frank's comments should you want to upgrade your braking. I am sure there are current members here who have done this. I have not.
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