Two Stroke Motocross
Two Stroke Motocross Forum => Technical => Topic started by: Taco on July 08, 2011, 07:08:01 PM
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How do you get the Swing Arm Bolt? I've hammered it for a whole hour and no budge! Will a torch work? Is there something special I need to do before removing it?
Back story: After I did my top end, I decided to replace my swing arm, rear hub, and shock linkage bearings since they were all loose. After taking everything apart I've found out I was right and most bearings are ceased. However, I cannot take out the swing arm bolt, which I obviously need to replace the swing arm bearings! I'll take pictures and videos if it helps. Thanks!
Here is the bike before the rear suspension was taken off.
(http://img837.imageshack.us/img837/4171/backyarduz.jpg)
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I have the same issue with my vintage 1976 yamaha 125. I heard of some folks have success with air impact hammers.
My plan is to lay the bike on its side with maybe a large socket holding the frame up from the far side so the bold can slide through a bit if it breaks free. This keeps the frame from "spreading" and taking some of the energy of the hammer blow away from whatever it is thats binding the shaft. Once this is setup I will whack away with an air hammer.
I probably will not get to it for a couple of weeks. Operation is ok for now but it does have to get done... Good luck with yours.
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I had success once with laying the bike over and spraying the bolt (with nut removed obviously) with PB Blaster over the course of a day or two. Then I took a large punch (I used a junk 1/2" extension) and a 3lb hammer and got violent and it finally came out.
It might also help to remove the shock so there is no compression on the bolt.
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Damn, it's a lot more work than I was expecting! The PB blaster idea sounds good. I'll get some, take the gas tank out, put the bike on it's side and spray some on the bolt. Wait a couple of days and hammer away. I really wasn't expecting it to be this tough, I used a metal cylinder and a 10lb hammer and nothing. I did strip the bolt, and I already ordered a new one. This is annoying. :\
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Well really it shouldn't be that tough. It should just come right out. Whoever owned it before you obviously didn't believe in proper maintenance or grease.
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You've probably mushroomed the bolt by now.A few thou expansion and "It ain't going anywhere".Measure the O.D. and I.D.of the swingarm bolt,get a selection of sharp drill bits stepping up from the I.D. to the O.D. and,with a portable drill,carefully start drilling out the swingarm bolt.It won't matter if you can't drill all the way thru. as you can use the "step" in the centre to drive out the swingarm bolt with a drift once it starts getting thin (and weak). ;D
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I had an old CR that did the same thing, i made a cradle and tacked it to the frame so it would hold it off the floor. I lay it on it's side and soaked with penetrating oil and left it overnight.
I bashed the f**k out of it with sledge hammer and it didn't budge. Had to cut it into sections to remove the swingarm and press the bearing shells out with the shaft still in.
Really highlighted the need for regular regreasing.
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I just had the same issue on my son's quad (99 Honda 400EX). The bolt had never been out.... I put it on its side and sprayed and sprayed it pb blaster.... nothing it would not move.... I ended up cutting it with a torch. The part of the bolt that was still in the engine had to be pressed out. (It still took 3 days in the press before t cam out)
When we worked on my buddies KX 125, we laid the bike on a cement block, as it has holes when the bolt could go into. It took a three pound sledge and a lot of persuasion, but it came out...
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Well, have you had any luck with this?