yz400f help with swingarm bolt

6 replies to this topic
  • OrangeMan73

Posted February 26, 2011 - 05:55 PM


Hey y'all, I'm dissassembling the bike completely to regrease moving parts, paint the frame black, and check out the innards. Right now I'm kinda stuck on removing the swing arm, can't seem to get the bolt to come out that the whole assembly pivots on (goes through the rear of the bottom end of the engine as well as the main frame). Any thing I should know about to get it busted outta there? Like have the swing arm suspended?

Gosh its friggin cold and I am ready for spring riding!!

  • brentn

Posted February 26, 2011 - 11:10 PM


Probably rusted up real good inside there.

The swing arm pivots on roller/needle bearings. There are two bearings on each side in which there is a bushing that the swing arm bolt goes through.
Remove the rear shock bottom bolt and disconnect it from the linkage, the swingarm should be free of tension possibly making it a bit easier to get out.
Either way it sounds like your going to have to pound it out.

I would use a heavy weight hammer, you can try a regular one but usually these bolts are in there real good when they rust. With a heavier hammer it will come out, use some penetrating lube where the joints are etc, and a socket extension or piece of bar stock etc.
Be prepared to replace all of the bearings and races. The races must be pressed into the swing arm and they are to be positioned at specific depths. The service manual will tell you the specs, if you don't have one someone here might be able to tell you the specs.
Bearings are usually sold in kits, or you can buy them from the dealer individually, although the kits give you all the parts you need in one package.

  • mikewrf18

Posted February 26, 2011 - 11:31 PM


Another thing you can do, is after removing/loosening the swingarm bolt nut, thread it back on a few threads. Then when you are pounding on the swingarm bolt with the nut on it you wound flaten/pancake the swingarm bolt. After you get it to move, then you can take the nut back off. If you flaten the swingarm bolt you'll have to cut it, and buy a new one, and I'm sure you don't want that. Also let it soak in PB blaster or something similar over nightt before trying to remove it, if it's seized up in there. Good luck, it's a real pain, I did mine a couple months ago. The tips I just gave you I learned from another TTer when I went through this ordeal. Just passing it along.

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  • negcash

Posted February 27, 2011 - 07:45 AM


You mentioned it was cold, maybe try a little heat along the length of the mounting. cutting and penetrating fluid may not be of any help (same seals that keep water out might keep out penetrating fluid) and if you cut it then you'll just have two stuck pieces

  • StoneRacer

Posted February 27, 2011 - 11:41 AM


I have one froze up on my banshee, a hammer did not move it at all:bonk:
i hit it till the end mushroomed & had to cut abouy 3/8 off to get the nut back on:thumbsup: if u look at that bolt there is a hole in the middle of it, get some all thread some nuts & a short length of pipe and use that to pull the bolt out :thumbsup:

  • OrangeMan73

Posted March 01, 2011 - 08:14 PM


Hey thanks guys for all the help. I disconnected the monoshock and put some liquid wrench on it overnight, and tonight it hammered right out (with a wooden dowel). Again, thanks for all the help, hope I can help a guy out like that someday.

  • StoneRacer

Posted March 02, 2011 - 03:07 PM


when you put it back together grease up the bolt good

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