.

Yes, this Montesa really is out to get me and trying my patience big-time!

The cases required some gentle tapping to separate the crank and bearings (as expected) but a lump of rust on the bearing has left a nice gauge as can be seen, and there

Two options I can think of.

See if there is an oil seal available with the same O/D but smaller ID and grind that section of the crank down to suit. or failing the availability of one make an adapter to increase the O/D of a smaller seal.

or

Get the crank metal sprayed and grind back.

Feel free to contact me to discuss if you need to, I know a local company in Poole who does metal spraying, at least they did. But I have to take Bulto frame there for grit blasting this week anyway so shall find out.

I have a cylindrical grinder in the workshop if you want to try.

Wayne...

Thanks for the reply Wayne

Metal spraying yeah, that could be a solution.

Got a couple of leads on some engine parts, will see what that turns up first, but its all getting a bit expensive for what was supposed to be a quick project, hmm...

Steve

There is another option I thought of after posting yesterday and thats to get a inner raceway designed for needle rollers.

Get one the same diameter as the std crank journal and the largest inside diameter available. Turn the damage off down to a transition fit to the raceway and shrink it on. This would rely on your original crank centres being still in good order, though it can be made concentric other ways.

This method is probably the most cost effective.

Wayne...

My Montesa rebuild has been on hold for a while but ready to start again now.

I took the crank to a local engineering firm who ground down the crank and all is well again! They only took off .1mm, which according to them is well within tolerance of the seal, and I would have to agree.

Well, see my next post, need some opinions on this!

Steve

Hi mate

Your problems are less likely to be than when you try to get that bloody primary gear off. I wish you lots of luck and patience. Get a couple of your mates, a slab of beer, an oxy torch, a good quality puller, and let everyone have a go at removing it. Failing that take the motor to your motorbike mechanic to get it off and then sit down, drink the rest of the beer, if there is any left, and then think about the original problem.

Hi mate

Your problems are less likely to be than when you try to get that bloody primary gear off. I wish you lots of luck and patience. Get a couple of your mates, a slab of beer, an oxy torch, a good quality puller, and let everyone have a go at removing it. Failing that take the motor to your motorbike mechanic to get it off and then sit down, drink the rest of the beer, if there is any left, and then think about the original problem.

Oh and be sure to wear a hardhat. When it eventually comes off it does so with an almighty bang and everybody runs for cover.

Well, of course I have already removed the infamous primary gear to be able to examine the crank

Edited June 30, 200917 yr by thedktor

Gday, you need a thing called a Speedy Sleeve which is designed to repair shaft damage like that. They are a thin Stainless sleeve which you tap over the shaft after the bearing is fitted and the seal will run on that. Obviously you need to clean up the damage first but that shouldn't worry the bearing. In Australia they are available from all bearing sellers. They come in various size ranges so you measure your shaft and then match the one you need. Easy to do and much cheaper than any other option.

Cheers,

Stork

Good info thanks Stork.

The engineering company who cleaned up my original crank were going to put a sleeve on themselves, after reducing the shaft diameter, and then grind it down to original spec.

But they only needed to take a small amount off in the end so left it as is. The new seals sit on there good and tight so I'm happy.

Steve