Hi guys,

I made a post the other day explaining I had lost drive and guessed it was a gearbox problem. I was wrong!

After removing the chain case this morning, it was apparent the cush drive bearing nut on the end of the crankshaft had come loose so no drive between the engine to clutch/gearbox/back wheel.

On examination it appeared almost impossible to get a lock nut onto the end of the crankshaft. I then read the manual!

It appears there is lock nut of some sort (missing on mine obviously) to be held in place by the cush drive bearing nut which is quite large and has 4 slots in it and needs a "C" spanner to tighten it.

I have ordered the "C" spanner and lock nut washer from Russell Motors this morning so hopefully back on the road by the weekend.

Much happier now that I was when loading the bike onto the trailer!

Regards
Roddy

email (option): rhvallan@ifb.co.uk

That lockwasher is a real PITA to get it working; I solved the problem by making a nut that enters the few threads still available in the cush drive nut; 2 holes to accomodate a pin spanner, some Locktite, problem solved...

Hi Hans,

Do you (or anyone?) know the thread profile on the end of the crank?

I think I will try and make up a nut or locking device similar to what you did. Thanks.

Regards
Roddy

email (option): rhvallan@ifb.co.uk

Sorry Roddy, my memory is'nt anymore it never was , and to open the primary drive again is a bit too much for this weekend, but perhaps others will help...

Hi,

Ok, understood, no worries.

I guess I could buy a spare nut and get it cut and
machined to suit. Thanks.

Regards
Roddy

email (option): Rhvallan@ifb.co.uk

Hi Roddy,

Threads on the crank is 3/4" x 20 tpi

It is a commom problem that this nut comes loose and running with it will give wear on the distance piece between the bearings and oil flinger plate fitted against the flywheel, this wear will upset the axial position of the crank in the crankcase. A loose nut can also cause the innerbearings to turn on the shafts so it is very important to keep this nut fully on.

I use a aluminium drift to thighten the nut and it never came loose untill today. (but don't ride that often...)

Cheers, Michiel

Hi,

Thanks for the thread info. I will try and come
up with a suitable solution.

Regards
Roddy

email (option): Rhvallan@ifb.co.uk