How to loosen rusted frozen shift drum and forks?

[skiri251]

Hi,

My Bridgestone 200cc motorcycle engine rebuild hit the wall.
It has a horizontally split crank case.

Gear shift drum and forks are rusted frozen in upper case halve.
I have to remove the forks from the drum before I can remove the drum from the case.

How can I do that?
I put a drift from neutral switch hole in the case (from the right side in a photo) and hammered hard to get to this stage.

One fork moved on the drum a little but I don't think I can go further without damaging the drum end and/or the case.

I am thinking about heating it with propane torch. Any precautions?
Any other way to loosen them?

 

[slabghost]

Slobber the parts with penetrating oil. Then beat the parts into moving with a brass hammer or chunk of lead. If you do use heat be aware too much heat will make the parts softer by annealing. Prior to any of this you might want to soak the parts in cider or something to remove the rust. That alone may free them enough to remove.

edit- Evaporust comes to mind.

 

[skiri251]

ahh.. evaporust.
I used it before woth good result.
Thanks.

 

[slabghost]

Let us know how it works out. It sure would be interesting to have a guy like you as a neighbor.

 

[skiri251]

Currently in evaporust dip. Will let it sit overnight.

 

[Omega Man]

opcorn: !

~O~

 

[Steve83]

Gotta love Evapo-rust!

 

[skiri251]

Evaporust worked!
No need for the torch.

Thanks a million!

 

[dan filipi]

Gee that's some good stuff!

 

[Steve83]

Excellent!! :clapping:
It really is good stuff!

 

[slabghost]

Congratulations! Looks like the parts will clean up well to serve once more.

 

[Ansimp]

That is impressive :good:

 

[Terry]

I used about 1 1/2 gallons of the stuff on my GL 1000 project on the fuel tank and other items. The stuff is very impressive.

 

[slabghost]

Any updates on the rebuild?

 

[wheeljam]

Where can I find this EvapoRust Product??

 

[slabghost]

Harbor Freight carry's the stuff. I'm not sure what other stores.

 

[wheeljam]

Ok Thank you

 

[Ansimp]

Super Cheap Auto here in Oz finally :good:

 

[skiri251]

slabghost » Mon Dec 28, 2015 5:29 pm[/url]":328nfcqf]
Any updates on the rebuild?

Sorry.
Just came back from 4 day camping at the desert.

Well, I think the crank needs to be re-built. At least one of three bearings needs to be replaced (doesn't move at all even after a night in EvapoRust dip).
I am not sure about the condition of big end bearings etc. Ideally they should be replaced.

Tranny bearings move but feel rough so they should be replaced.

Left side cyclinder wall got chrome plating peeled off so it needs to be re-chromed.

So I am looking for parts and places who can disassemble pressed in crank and press back them together...

 

[slabghost]

Harbor freight has presses at reasonable prices you'll probably need to make your own braces and such.