Bent Frame - Advice Requested

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Tim

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Feb 4, 2009
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The new project is pretty much taken apart and in boxes and baggies awaiting repair. My current problem is how to deal with the bent frame. This bike came from Arkansas and back in the 70's some "safety expert" convinced the Arkansas legislature to require all motorcycles to be equipped with "crash bars". They were attached to the frame down tubes using u-clamps. The result is a bent frame where the clamps were tightened around the bars. I request some of your good advice on how to deal with this issue. The frame is in excellent condition except for this.

Bent Frame - Advice Requested


Any advice would be appreciated. I haven't a clue.

The engine is out on the workbench and ready for a teardown. I'll keep you posted.

Bent Frame - Advice Requested


Thanks
Tim
 
Sad deal, man.

I would think that a good fix would be to cut out the bent sections, straighten them (or replace with straight pieces), then weld them back in place with sleeves slipped over the cut joints.

I'm not a framecrafter, so I can't say what the BEST or recommended fix is. Straight frames can be found pretty inexpensively, but the SHIPPING is what gets you!
 
grandpaul said:
I would think that a good fix would be to cut out the bent sections, straighten them (or replace with straight pieces), then weld them back in place with sleeves slipped over the cut joints.
Grandpaul
That's pretty much what I'm thinking about doing. I've had it done on aircraft frames and it worked well. I was hoping someone would have a different idea.
Thanks
Tim
Click to expand...
 
ludwig said:
If it is just a dent , you could take the opportunity to weld a cross tube at that spot , like is often done .
You can cut the cross tube so that it covers most of the dent . Fill wat remains of the dent with lead .
Click to expand...
Ludwig
That's an idea I hadn't thought of. Does anyone have a picture of a Commando frame with a cross tube welded in?
Thanks
Tim
 
There are shops that can bring shit back from the dead way worse off than that Commando frame.

Find a shop with a proper frame jig and get them to replace the sections. You may have to ship that frame if you can't find anyone locally or don't want to do it your self but it can be saved, that's for sure.
 
That's an idea I hadn't thought of. Does anyone have a picture of a Commando frame with a cross tube welded in?
Thanks
Tim[/quote]
Bent Frame - Advice Requested

Here you are.
 
My Hyde oil cooler clamps across the downtubes in two places right about there and would provide camoflauge and reinforcement--the crosspieces are solid aluminum and about as rigid as a tweek bar.


Tim Kraakevik
kraakevik@voyager.net
'72 Combat
 
I suggest drilling a 3/16" or so hole on the opposite side of the dent. Then take a punch and go through the hole and pound out the dent the best you could. You should be able to get it pretty close. You can leave a few "lows" in the dent but leave no "high" spots. Then have the hole you drilled filled with a weld. The hole can be beveled or ground to allow a contour that allows proper weld. You need a good weld here and this is the key to making this a quality fix. Grind the affected area and smooth with a filler and paint. Minimal cost, minimal intrusion, solid repair.

I personally would not want to cut the frame in half to deal with this dent. In order to insert a sleeve you will have to cut it in 2 places. I would feel safer riding on a frame repaired as I indicated as compared to one sawed in half. Then there is the cost thing.

Your dent is not that bad and if you can pound it out should be nearly as strong as when you started.
 
nortonspeed said:
That's an idea I hadn't thought of. Does anyone have a picture of a Commando frame with a cross tube welded in?
Thanks
Tim
Click to expand...
Here you are.[/quote]
Nortonspeed
Thanks. That looks good. I had to look twice to even notice it. I'll definitely consider doing that.
Tim
 
Tim said:
Nortonspeed
Thanks. That looks good. I had to look twice to even notice it. I'll definitely consider doing that.
Tim
Click to expand...

I too was busy looking at the rest of the bike. :mrgreen:
 
Nortonspeed, that is one gorgeous bike. I think that Dreer's 880s had a cross tube right around where yours is, makes sense.
How do you keep those mufflers on??
 
ludwig said:
If it is just a dent , you could take the opportunity to weld a cross tube at that spot , like is often done .
You can cut the cross tube so that it covers most of the dent . Fill wat remains of the dent with lead .
Click to expand...

LEAD, do you know how HEAVY lead is , in this time of light weight space age fillers, Ludwig I'm shocked
 
Lead will not shrink or come loose and can be powder coated, I gave a lead loaded Interstate tank and in 20 years there have been no issues with the repair.
 
Bob, those might be the type of mufflers that have the integral split sleeve that clams down with a small through bolton the backside.

Viking, maybe?
 
bpatton said:
Nortonspeed, that is one gorgeous bike. I think that Dreer's 880s had a cross tube right around where yours is, makes sense.
How do you keep those mufflers on??
Click to expand...

Bob, the cross tube was standard on the Truxton Club Racer Commando to be sold during 1975.
You have to ask Holland Norton Works about those mufflers (it's their "Perfect Commando") :wink:
 
Lots of ways to do it for sure. I would also be tempted to do a brace and fill with lead or maybe brass by brazing.
All I currently have is an oxy acetelene rig and I don't like the idea of welding frame with that.
 
What I am about to say is grounds for hanging, banning, but here goes.

Just my personal opinion, those indentations on the frame tubes do not look that bad, seriously, they don't.
In 1971 I bought my first Commando and immediately put highway peg bar that crimped on the tubes, and rode that
bike from Minnesota to Mexico and back home, with my feet on the bar.
And then took the bar off and rode it another 10 years and 20,0000 miles before selling it. No handling issues.

I bought my present 850 17 years ago and it had a little worse looking tube indentations from the previous owner.
I sanded down those areas, mixed up some JB Weld and built it up, then sanded down and painted, looks perfect.
No issues, no funny handling, nothing but happy riding every since.

YES, I know what the "right" thing to do was, do what everyone here has suggested.
But I did not bother with both bikes worse looking than yours, just don't see how the frame is "weakened" or how you would
be in any danger while owning and riding the bike "normally", not as a stressed racer.
Ok, throw me off, tell me I am giving bad advice, I know, I know. Just saying what I did with the same issue.
 
The tube can't possibly resist bending as well as when there was no dent, but as I understand it, the stress on the front downtubes is mostly the tension of the sheer weight of the motor and literally pulls downward on the steering neck, so maybe the dents aren't actually dangerous. I think the large backbone tube takes most of the bending and twistin stress of the motor putting power to the rear wheel and the front wheel steering, so possibly bondo and paint is harmless.
 
Probably not dangerous, but if all the force was downward, what is the advantage of adding the cross brace on the race frame? If your riding style is such that you do a lot of fast riding in the twisties, you may experience some flexing (or cracking :shock: ), but if your style is more leisurely cruising, you will not likely notice any difference. It definitely will be a weak point.
 
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