Crack in swingarm

13 replies to this topic
  • millzy555

Posted April 18, 2006 - 05:35 PM


Guys upon buying my bike i noticed a crack in the swingarm, where the weld is. Now it is only a hairline crack but i want to get it fixed. Would it be possible to just weld it back together: MIG/ TIG/ ARC. my dad has all the welders but wondering which one would suffice. Is this going to fix the crack or will it just reappear?

thanks jordan

  • beezer

Posted April 18, 2006 - 05:39 PM


It isn't cracked, they all look like that.

  • millzy555

Posted April 18, 2006 - 05:56 PM


Are you sure?, the mechanic said it shoiuldn't be like that. Anyway bike is at the shop getting a general look over so i can't take any pics, i will post it up tomorrow

  • millzy555

Posted April 20, 2006 - 05:54 PM


ok hope this works


new bike:

  • Norman

Posted April 20, 2006 - 06:07 PM


Looks like a crack to me

  • millzy555

Posted April 20, 2006 - 06:14 PM


should i weld it, or just replace with a new swingarm, or let time take its cause and keep an eye on it

  • 35yz450F

Posted April 20, 2006 - 06:45 PM


Replace it.

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  • matt116

Posted April 20, 2006 - 06:46 PM


I have welded mine with great success. I used TIG with 4048 filler rod, a little pre-heat then a slow controlled cool down. I wrapped the swingarm in leather then a blanket and let it cool over nite.

  • Blue ARC

Posted April 20, 2006 - 06:48 PM


Wow that's a bad crack. Because it's aluminum it could get a lot worse fast. I wouldn't jump that's for sure. You should fix that as soon as possible. Tig is your best bet as you have the most control and finesse. Make sure you grind the crack out and go past the crack at least 1/2 inch when grinding. When welding makes sure you overlap the existing weld and don't leave a crater in your puddle or a crack will form again. If you need more info let me know.

  • fastbyfrank

Posted April 20, 2006 - 06:54 PM


thats a crack for sure, common problem on yz's caused by factory chain slider moving around. the crack can be ground cleaned and welded, it looks like it is opening up, which means that it will have to be closed for proper alignment. you may be able to find a nice swingarm used on ebay etc.. and it may be cheaper than the repair. hard to say. my experience with aluminum is it tends to crack again in the same spot.

  • viking_in_wa

Posted April 20, 2006 - 07:15 PM


my career is welding and that crack looks easily fixable to me, you need to grind or bevel out the crack and stop drill it on both ends and just lay a nice bead right through the groove you made. mig or tig would both be ok but tig is probably the best bet so you can keep the heat out of it.

  • Raven1911

Posted April 20, 2006 - 07:16 PM


Weld it! Then, Go to the late Motomans website and click on tech articles on the left and then scroll down to 'misc' and click on 'fixing the faulty swingarm slider'. Its a good article. Most likely your swingarm slider is too loose from the 'tophat' type washer that is not crimping on the swingarm slider. Its a quick fix and it prevents the crack in the future. The swingarm slider slides back and forth on the swingarm when the chain rolls on it and grinds the metal away and causes the crack.

  • millzy555

Posted April 20, 2006 - 07:31 PM


thanks all for the replies. Although it looks bad the crack isn't that deep so maybe i'll just weld it. I think the bolt on the chain slider is loose so maybe that could be the problem

  • michmex

Posted April 21, 2006 - 05:27 AM


if it cracked at the weld i would get a hold of yamaha and just tell then that you bought the bike the weld look shity then when you were rideing it split im shure theyll understand and probly get some free stuff

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