How to cut off my swing arm with out damaging frame or motor

Hello, this is one of my first posts because normally I can find the answer to my questions by just using the search bar but this one has me stumped.  I cracked my swing arm on my 2005 yz250 right where the swing arm mounts between the frame and the motor on the left (sprocket side of the engine).  This has caused the swing arm bolt to get jammed and will NOT come out.  Thanks in advance for your advice.

20lb sledge and a torch if its steel framed, pb blaster if its aluminum, if not its gonna be quite a female dog to get out

I had to do this about 4 years ago on my old '93 cr250, my swing arm bolt was stuck nothing else was damaged. After many failed attempts to remove this bolt by pushing it through the motor how it should come out. I ended up using a wood splitting wedge to pry apart the frame and the swingarm enough where I could fit a sawzall blade in there and cut the bolt I then did this on the opposite side of the motor once I cut the bolt I ended up having the rest of the bolt pressed out by a local machine shop. This may have not been the best way to do this but there was a fair amount of beer and a lot of frustration involved, but any how it worked and the frame was not damaged I just had to get a new swing arm bolt. I hope this helps good luck.

Start by spraying a penetrating oil into the seams and crevices where the bolt goes through and letting it soak in over night.  Do this a few times.


Then as stated previously, you can use a little heat on the bolt and rear engine cases where the bolt goes through.  Be very gentle with the heat though as you have the aluminum frame and you can easily destroy your frame if you get it too hot.  You are not trying to melt the bolt, just get it warm enough to expand and break loose from the corrosion that is holding it in place.  I would use a propane torch if it was my bike.

Thanks for all the help. I tried all if what u guys suggested and nothing. Here is a pic of the swing arm ImageUploadedByThumper Talk1378929100.887966.jpg. You can see the crack on the pivot point. I'm pretty sure this is what's jamming it up.

Strip the bike (forks, wheels, tank, exhaust). as far down as you can. Take the bike (engine/frame/swing arm) to a machine shop. They will put it in a press and properly press the damaged bolt out.

You might try loosening all of the motor mounts so that the motor can wiggle a little separately from the frame and swing arm.  It might just move enough so that you can get the bolt out.

sawzall and a few metal blades will do the trick

snap on air hammer will get that out

Thanks everyone. This is a very late response but I actually ended up using a plasma cutter to get it out. That thing was seriously stuck in there.

And how did you go about using a plasma cutter to get it out without destroying other stuff in the process

Oh I definitely destroyed other stuff in the process! I ended up having to replace the swing arm and frame. The hardened steel race that goes between the swing arm pivot bolt and the actual rollers in the bearings got so corroded it actually pretty much fused to the swing arm bolt. I had to cut the swing arm off around the bolt between the engine and the frame with a dremel tool. I also went ahead and purchased another frame off fleabay and updated the swing arm. Luckily all the parts used for a yz are very reasonably priced. Let's just say the previous owner never touched a thing on this bike the entire time he had it.

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