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Can a cracked swingarm be welded

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aluminumgiraffe

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I bought a 2002 CR125 as a project bike off craigslist and after cleaning the swingarm I noticed a crack right along the weld. Is this something that can be fixed with a nice tig bead or am I out $500 for a new swingarm?

 

https://www.flickr.com/photos/125432373@N02/14401599496/

https://www.flickr.com/photos/125432373@N02/14401600066/in/photostream/ 

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Kawracr 173
Kawracr 173

I think most of these guys that doubt a weld are ones that have a buddy that bought a welder from a guy that knew a guy that watched his cousin use a welder. I weld for a living, and a lot of peopled

Kawracr 173
Kawracr 173

Not sure what your basis is for that input. But... I've been welding for 20yrs. All types of welding tig,mig, and stick. And yes welds can break. Aluminum in this case will not get weaker it will make

kaleidoscope eyes
kaleidoscope eyes

i would think that you could grind and bevel it out then tig weld it.

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orangyktmthing

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Take it to a competent welder, like Olhillbilly stated. Any welder worth his/her weight would be able to fix that easily, and charge you nowhere near 150 bucks. Hell, you could also bring it to your local community college (if they have a welding department) and you can have the instructors weld it up for just the cost of materials and they can show the students as a "demonstration". I had a inner clutch cover from a friend's kx 250 that ended up cracking (we call him dr. hamfist) while I was taking classes and I just dropped it off one night and picked it up after class, tig welded perfectly, at no charge.

Edited by orangyktmthing
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aluminumgiraffe

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Being new to this forum i appreciate all the replies, but it seems like the jury is out on whether I should weld it or buy a new one. I don't really have any connections with a good welder so I think I'm more inclined to buy the used one off of Ebay. Just seems like a better option considering this bike is mostly going to be spending its time at the track not as a beater woods bike and the last thing I want is that swingarm letting go on the face of a jump  :cripple:

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aluminumgiraffe

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the 500 bucks I was referring to would have been the cost of a new OEM one haha, which i guess is a moot point now considering the cost of one in decent shape off ebay

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orangyktmthing

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Being new to this forum i appreciate all the replies, but it seems like the jury is out on whether I should weld it or buy a new one. I don't really have any connections with a good welder so I think I'm more inclined to buy the used one off of Ebay. Just seems like a better option considering this bike is mostly going to be spending its time at the track not as a beater woods bike and the last thing I want is that swingarm letting go on the face of a jump  :cripple:

I would just do a search online for local welders, then look for reviews about the ones that you find. Looking them up, and stopping by with the swing arm would certainly cost a bunch less than a used swing arm off ebay. Another thing that you might want to consider is the probability of the used one on ebay possibly having it's own issues. The last thing that you would want to do is to drop 150 bucks on a swing arm, then have to spend more money to get it usable.

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Kawracr 173

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Being new to this forum i appreciate all the replies, but it seems like the jury is out on whether I should weld it or buy a new one. I don't really have any connections with a good welder so I think I'm more inclined to buy the used one off of Ebay. Just seems like a better option considering this bike is mostly going to be spending its time at the track not as a beater woods bike and the last thing I want is that swingarm letting go on the face of a jump :cripple:

Properly welded it will be just as strong as from the factory, Period. Surely there is a weld shop in your area.
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aluminumgiraffe

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Properly welded it will be just as strong as from the factory, Period. Surely there is a weld shop in your area.

I noticed where the crack ends there is a hairline discoloration mark, could this possibly be a stressed area that's about to crack? If so, would welding still be a viable option

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FulThrotl

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Being new to this forum i appreciate all the replies, but it seems like the jury is out on whether I should weld it or buy a new one. I don't really have any connections with a good welder so I think I'm more inclined to buy the used one off of Ebay. Just seems like a better option considering this bike is mostly going to be spending its time at the track not as a beater woods bike and the last thing I want is that swingarm letting go on the face of a jump  :cripple:

yes, it can be welded..... but....

as ebay is easily available..... i'd go there.

 

the main thing is preheating the aluminum, and the weld prep.

it takes a lot of heat to get penetration, and it's in a severe load

area. the oem was done on two manufactured parts, tig welded

by a machine.

 

i'd look at where it is, and how that's gonna work out if it fails.

it's not a silencer bracket.

 

it also seems to be a casting welded to an extrusion, which is

more likely to be a problem than similar material structure.

Edited by FulThrotl
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Kawracr 173

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I noticed where the crack ends there is a hairline discoloration mark, could this possibly be a stressed area that's about to crack? If so, would welding still be a viable option

Can't tell from pic for sure. When the crack gets prepped for welding, that's when you"ll most likely find out. The crack will "expose" itself in the sanding/beveling process. It can still be welded. Main thing is question their process. Preheat is not required but is helpful. Keeping it "warm" after welding is what's important. If it cools to fast, it will shrink at different rates due to density. That's when things go bad and it cracks on the bench. Make sure they use a 5356 tig rod not the 4043 it's for tool boxes.
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