Stuck swingarm bolt!

[cultofthumpers]

I have a 78 YZ250 I am disassembling and the main swingarm bolt won't budge. I have tried Kroil, put the nut on and bashed it with a hammer..... the swingarm will move freely but the bolt will not slide out. I am afraid to hit it with the torch as I want to save the alloy arm. Any advice? 

[vandy010]

they're a dead set prick of a thing to remove as the design of them has the bolt running through a steel sleeve and then they sieze on that.
bugger!
to press them out is the best option but a fiddly thing to set up as not everyone has access to the equipment.
once apart though, i like to machine a very small reccess in the swingarm bolt in the area of the steel "sleeve" which allows some relief for the bolt and helps to minimise the binding effect.
press the sucker out.

[mainline]

last resort is to cut the ends off the swingarm bolt, inside the frame brackets so that the swingarm drops free. Those ultra-thin grinder cutting discs work well.

You'll obviously need to get a new swingarm bolt and the thrust covers on the end of the swingarm, but they're usually rooted anyway. Swingarm bolts are pretty easy to find.

[mainline]

here's one of about twenty on ebay at the moment

http://cgi.ebay.com/ebaymotors/1979-Yamaha-YZ250-YZ-250-Swingarm-Bolt-_W0QQcmdZViewItemQQhashZitem35a89b9c55QQitemZ230462037077QQptZMotorcyclesQ5fPartsQ5fAccessories

[caps 999]

that is the best way to go what mainline because when i was working at a bike store we had to press a  swing arm bolt out of a 88 cr250we ended up having to put that much force on it it fractured the arm and frame

[suzuki 400]

my 2 cents worth 
use the torch to warm the area only then get some wurth rostoff (spelt that way)or my favorite brake fluid good for pistons stuck in bores as well give it a couple of good wacks with a good size hammer like small sledge on the protruding bolt end  do the same for 3-4 days ,the heat with the expanding  and contracting helps break the bond the rust has and also the vibration from the hammer ,this may not be a 10 min fix but i,ve had plenty of swing arm bolts and cv,s joints come out this way ,the grinding disc sounds a good idea as well ,back in nz had a mate in a machine shop drill thru both ends that worked a treat (he,s a clever bugger with flash tools )  rod

[Hoony]

if you do finally get it to move with a hammer, make sure you grind at least 5 mm off the end before you hit it all the way though as the end will be flared over by hard blows.

[Slakewell]

wurth rostoff is great stuff spray it on for a few days. I have used this meathod with success. Heat the bolt till it turns red then pour soulable oil mix with water to quench it,repeat this a few times. Use some timber to brace the frame or hold it flat. Use a brass drift held with vice grips to hit the bolt really hard with at least a 4lb hammer.

[brent j]

As Vandy says the bolt is probably siezed in the sleeve in the centre. This makes it hard to get any heat in to where you need it to dislodge things.
All you end up doing is heating the swingarm not the sleeve.

Try a mix of ATF and Acetone (50/50) and let it soak for a few days. If you want to press it it pays to set up something to supoort the frame CLOSE around the pivot bolt so the load is put where you want it.

An air chisel can be very effective in cases like this. Make a dolly to press on the end of the bolt. The repeated, sharp blows will often dislodge the bolt and keep it moving.

Brent

[Marc.com]

the heat won't shrink it off but repeated expansion and contraction will break up the corrosion a bit and allow oil, brake fluid  to penetrate.

heat the bolt head and poking out end red how while protecting the frame bit of wet asbestos blanket, old wet welding glove or something similar.

[rocketfrog]

Centre punch the threaded and head end of the bolt and start working up in drill sizes to the depth where the protruding portion of the bolt will clear the frame, use plenty of cutting fluid and take it slow. The last thing you want is a broken drill. This is slow and tedious and makes plenty of swarf, but it will work with out loading 20 odd tons of force applied by a press onto the frame, and I am not kidding. These things get stuck proper! I like the thin angle grinder blade technique though- if there was enough space to get in there I would definitely give that a go as well. Best of luck mate, most of us have been there if it is any consolation.

[pancho]

I was in at a Repco store yesterday and noticed that they had cans of that penetrating oil in a pressure pack can ,the type that uses a refrigerant [probably liquid nitrogen or similar]. I believe this stuff is very effective and has so far been expensive, however they have it for under $15.00. I think it could help and I'll be back for a can cheers..... old .....nut..s

[TT5 Matt]

the badly rusted swing arm bolt i had on a xt500 i brought that had been out in the weather for 4 yrs came out with 6 weeks of soaking with wd40 like 6 or more applications per day than blocked up level with a blocked up spocket of the right size on the head of the swingarm bolt to stop frame spead/damage,use a solid large pin with welded on handle and 7 plus pound hammer

[cultofthumpers]

My Gawsh what a bear to get out!  penetrating oil and bashing it didn't work, nor did an air hammer, I had to use a high speed cutter with a thin blade and cut the bugger out!
Now I need the caps and bearings. Anyone have a set? 

[Mike52]

My Gawsh what a bear to get out!  penetrating oil and bashing it didn't work, nor did an air hammer, I had to use a high speed cutter with a thin blade and cut the bugger out!
Now I need the caps and bearings. Anyone have a set? 

Beauty mate, now what are you like on husky primary drive gears?
Seems to be stuck