Frame damage?

[Senior Gonzo]

I've been tearing down my 1979 GS750L for a while. Finally got it down to the frame. I noticed that there's a bent/damaged/torn part of the frame on the bottom. When I moved it, dirt or rust fell out. Before I start putting a lot of time and money into parts, I wanted to make sure that this isn't going to cause the bike to be unsafe. Is it repairable? I'm a novice and this is my first project bike, but I'm pretty mechanically minded and don't mind tearing into stuff and learning.

[Guest]

I would tilt the frame around to let any water in there drain out, then weld the hole up with a TIG or MIG welder and carry on.


Mark

[rustybronco]

That my friend is called rust through. There is also what looks to be a little bit of splitting of the frame from water that had frozen inside it.

Is it repairable? Everything is. The question is, do you have the equipment and skills to repair it?

[barnbiketom]

that scares me. bang gently around the area with a hammer to see if the surrounding area is weak or thin. if so then "I would look for another one" since i'm not into fabication.
when you see rust, there is more. water has gotten inside that tube, frozen and split it. how much more bad area is the question.

[jbird7262]

Any shop that builds or customizes bikes or hotrods should be able to fix you up, cut out the section, put a piece of chrome moly tube in, weld her up. You can't slug it because its in the middle of a tube section. Or you can split a section of tube and band-aid it. Not a big job, if your going for concourse restoration or just safe repair its all repairable.

[Senior Gonzo]

I have access to a welder at work, but you're saying I can't just weld up the hole? I'd need to weld something over it as a patch?

[rustybronco]

First you need to find the extent of the damage. How far does it extend? Is it confined to just the one side or is the other side affected as well?

Only then can you formulate a plan of attack.

[chuck hahn]

OR find a good cheap untitled frame and swap steering necks.

[KatManDo]

I have access to a welder at work, but you're saying I can't just weld up the hole? I'd need to weld something over it as a patch?

Rustybronco is spot on with his advice. That hole is nothing more than the end result of a much greater corrosion issue within the tube. If you try and weld just the hole you'll be chasing your tail as you burn the hole larger and larger. Rust is not metal, it's an oxide and has zero strength. Investigate the extent of the damage and then you can formulate a plan. Either cut out the tube and replace with a correct dimensioned and quality pipe OR find another frame with papers. Don't mess around with the structural integrity of your frame or your personal safety by taking short cuts. Good luck !!!

[Guest]

Rustybronco is spot on with his advice. That hole is nothing more than the end result of a much greater corrosion issue within the tube. If you try and weld just the hole you'll be chasing your tail as you burn the hole larger and larger. Rust is not metal, it's an oxide and has zero strength. Investigate the extent of the damage and then you can formulate a plan. Either cut out the tube and replace with a correct dimensioned and quality pipe OR find another frame with papers. Don't mess around with the structural integrity of your frame or your personal safety by taking short cuts. Good luck !!!

OR find a good cheap untitled frame and swap steering necks.

What they said. I don't know, though would drilling a hole at the bottom of the bends of the down tubes so any water could drain be a good idea?

Anyways, I've seen some L frames on Ebay whether they were titled or not, couldn't tell ya.

[posplayr]

If that was a rotted vintage 4:1 exhaust, I would try and patch it but there is very limited structural requirements. For a frame member, I would never try and patch frame like that unless you know exactly what you have.

How are you going to determine how much rust damage there is throughout the frame?

[Brendan W]

I think Rustybronco is correct. If you were sure it came from a recent impact you could, after checking out the full extent of it, go for repair. Unfortunately to me this looks like extensive internal corrosion has happened. Not only that but it's an important member of the frame. Whether the hole caused the corrosion or vice versa doesn't much matter at this point. Is it repairable - yes but I have the feeling that any responsible frame repairer would feel uncomfortable with it and probably suggest that used frame is a better option.

[Gregory]

I don't recognize the part of the frame, and since no one else said this, it is probably wrong...but when I look at your picture it sort of looks like something may have been cut off the frame and been cropped too close causing the hole.

If it were me, since I have a welder, if that's all it is I would weld up the hole ... or if rusted out badly, I would put a rod inside, or sleeve outside and re-weld. If people can make frames from scratch, I don't see any reason why someone with good welding ability cant repair or modify a frame. You have the hard part done with the engine off of it.

[Senior Gonzo]

I've checked over the rest of the frame and can't find anything else that would indicate a hole for water to get inside or other damage. I hammered around on the area and nothing seemed brittle. Even hammering on the actual split part, nothing chipped off, it just started bending back into shape as it was hammered.

How else would I go about checking out the extent of the damage? Grind/sand around that area? I was planning on doing that anyway for repainting.

[rustybronco]

My GS1000EC has a weep hole drilled into the bottom of each lower frame tube.

As for checking for further rust damage, the only practical way for the home mechanic to find the extent of the damage, is to start cutting away until you find solid metal again.
If you do decide to go this route and need to remove a section of the frame, make sure you brace it rigidly first.