Fox .40BB deluxe crank removal

[Ron Cribbs]

Looks to have a tapered collet between the thrust washer and crankshaft.

I figured it was a press fit, but I can't get it to budge. Am I missing something?

[Brett Buck]

Looks to have a tapered collet between the thrust washer and crankshaft.

I figured it was a press fit, but I can't get it to budge. Am I missing something?

 

    I haven't seen a Fox like that, but the tapered cone type frequently requires a puller. I use a battery terminal puller ground to fit properly behind the washer. Crank it tight, then tap the end of the screw on the puller with a hammer, and it will almost always pop right off.

   Brett

[Clint Ormosen]

You may have to heat it a little to expand it. Usually though, a few taps on the crank to the rear pops it right off. Never had to use a puller.

[Andrew Hathaway]

It just so happens that yesterday I came across a cache of PDF manuals for Fox engines.  The following is an excerpt from the Fox 45/50 manual.



Personally, they lost me at pliers.  I think I'd try heating the washer with a heat gun and rap the crank and/or washer with the block of wood.  Of course I'd exercise care to avoid bending the crank, or damaging the washer, or pushing the crank into the back plate in the process.

I'll try to attach the Fox 45/50 manual PDF, credit goes to whichever RC forum I found it...

[Ron Cribbs]

Thanks Everyone,

I'll take a "whack" at it again today.

Andrew, would love to have that manual...

[Andrew Hathaway]

Thanks Everyone,

I'll take a "whack" at it again today.

Andrew, would love to have that manual...

Look at the bottom of my previous reply, there's a little paperclip, click where it says 45man.pdf and you should be able to view or save the manual.

[Motorman]

If you heat the washer don't take the temper out of the prop shaft.

[Ron Cribbs]

Ok,

It's apart. Required far to much force for my taste. Must be an easier way to do that.

Anyway, thanks for all the advice everyone.

[Steve Helmick]

The Fox sounds just like a Super Tigre...an excellent setup, IMO. You're looking for a minimal axial movement of the crank. Bending the rod is not desireable, but .035" (1.00" divided by 28tpi) axial movement isn't going to do that. The shaft needs just a slight axial "adjustment" to loosen the collet & prop driver. Actually, .010" would do it.     

My SOP would be to take off the backplate, back off the prop nut one half to one full turn (with prop installed), set the backplate area of the case square on a block of hardwood, like a bit of 2x4 on the floor, bench or vise. Gotta clear the upper bits of the cylinder, muffler doodads, etc. Give the end of the crankshaft a sharp rap with a small deadblow hammer (24 oz). If that doesn't get it, then screw another (sacrificial) prop nut onto the exposed end of the crankshaft and give it a sharp rap with a small metal hammer (12 oz ballpeen). Make sure you have a little gap between the nut(s) and washer, and it'll work.

Is this excessive force? I don't think so, done it that way for 50 years on a lot of Super Tigres. Other than burned up or just worn out piston/cylinders, I never had any problems with cranks, bearings, rods or circlips...even homemade circlips worked just fine.    Steve

[Ron Cribbs]

Thanks Steve,

That sounds simpler and safer. I didn't damage anything, but like I said I had to give it a good whack before the thrust washer popped free of the collet.

After that dissassembly was a breeze.