Bent frame. What do I do?

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Coco

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Just noticed I have a slight bend in the right side front down tube. I can't believe I've never noticed it before. The bend is about halfway down the tube between the bottom of the stem or head tube and the front iso mount. I bought the bike, rode it a few times then started into the rebuild so I can't say if the bend is having and adverse effects on the handling. Everything else seems ok.

Can I just take this to a credible body shop and have them attempt to straigten the tube? I noticed it because I was about to send the frame to powder coat on the weekend and am cleaning the gunk off. I happened to look at thef ram from the right angle and noticed it. You can actually see two points of impact on the two front down tubes but can't figure out how it could have happened with the front forks on the bike. :?:
 
Coco said:
You can actually see two points of impact on the two front down tubes but can't figure out how it could have happened with the front forks on the bike.
Click to expand...

Do you think the damage could have been caused by impact to a crash bar that had been fitted (and then removed) by a previous owner?

Are the two damaged areas at roughly the same height on each of the down tubes?
I know you said that one tube is bent but that there are "points of impact" on both? Could that 'impact' damage look as if it could have been done by crash bar mounting brackets? I seem to remember reading a long while ago, that the fitting of crash bars to Commandos was not recommended, as they were likely to bend the frame in an accident.

My own Mk3's down tubes bear some minor clamp scars lower down, probably caused by fairing brackets, as I believe mine was originally built as a police Interpol model, which would have had a fairing fitted originally.
 
Coco,
LAB could well be correct, I too had a frame with crash bar damage but was able to pull the bends out with the aid of a strong back made from heavy angle iron and three hard plastic saddles.

Cash
 
Points of "impact" where the paint has been chipped and touched up are level on each side. Your comments about crash bars are probably correct.

The thing that angers me is I didn't even notice that when bought the bike. It is not major and I think I can bend it back. I have two hydraulic presses here at work. I might sandwich the tube between some wood and gently press it straight. Is that a bad idea?
 
Hi, If it were my frame I'd find a good frame straighting service, there are frame checking dimensions at http://rocbo.lautre.net/technique/norto ... p/084.html .
Certainly straighten out the down tube yourself, but be very careful you don't crush or kink the tube in any way, a good idea is to bore a hole the same diameter as the tube in a block of hard wood and then saw it in half through the center of the hole and use this as padding for your hydraulic ram. After you finished I'd get the frame professionally checked out by someone who knows what there doing and get it pulled back to factory specs. A lot of old bikes could do with the same treatment as we have no idea what accidents the bikes has have in the past four decades, and what unnoticeable changes there has been to the frame alignment as a result.

Graeme
 
Good point Graeme. I was going to use wood as a buffer. I also am going to try using a frame straightening jig used for bicycles. I've used them before in my bicycle wrenching days and it might work on the small diameter tubing on my MKIII frame. I've bent back chrome-moly frames before but it was much easier on a bicycle with the proper tools. I'm going to see if that will work, then I'll contemplate things before I stick it a press.

Unfortuneately there are no frame straightening firms where I live and none that I know of close by.
 
Another item to check while you're rebuilding - the forks. I didn't notice anything unusual with mine until I had one fork tube out and on the bench. It had a very slight bend where the bottom clamp met the tube. The other fork was fine, but my local shop sells them by the pair, and I now have one straight and one slightly bent 'cheater' bar.

My 850 apparently had a couple of minor lowsides in its life, causing some damage to the speedo (cracked bezel), speedo and tach pods, master cylinder, left fork, kickstart lever, right foot peg, clutch lever and the bottom of the left silencer.

I guess that's not too bad, considering the age of the bike. I think I had more scars by the time I was 35!
 
It is possible to "ease" the downtubes back into position if they aren't too badly damaged. In the event of a front end shunt the wheel / mudguard usually ruins the frame, they aren't that strong when hit that way.
This photo is of a mate of mine in Belguim who hit a car at 30mph last year!!

Bent frame. What do I do?
 
Gino Rondelli said:
This photo is of a mate of mine in Belguim who hit a car at 30mph last year!!

My experience of destruction testing Commandos say that his speed was closer to 60 mph ! :)
Click to expand...
 
79x100 said:
My experience of destruction testing Commandos say that his speed was closer to 60 mph ! :)
Click to expand...

I have to agree, based on my own crash testing! Perhaps 30 mph is what he told the police? :wink:

Debby
 
I seem to better off than I thought after seeing those pics. The bike has no eveidence of a crash and the bend is ever so slight since I never noticed it before until the bike was down to a bare frame. My forks are dead on straight so no problems there.

I'm going to put some 7/8" round bar through the bearings and rest the fram on a level surface and measure the angle of the piece of roundbar. That should tell me if the frame is square, which I think it is. if that is the case, I'll leave the slight bend and fill the ding with some JB Weld before it goes to the powder coater.
 
Frame is worse than I thought. Other side of front downtube is bent also. Looks like a bit of a twist going on. I left it with a frame manufacturer here in town (Harley/V-twin stuff) and hopefully they can straighten it out.

If they can't, is there anyone in Canada that can repair my frame?
 
Not much news on this. Frame still at local harley frame builder. Hopefully they dont mangle it even more.
 
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