clutch spacer and lock washer

[AdrianS]

In the process of putting the primary drive back on the A50.
Now, Haynes manual is next to useless and the BSA WSM is not much better especially as no good pictures.

Spacer behind front sprocket, rotor, lack washer with "tang"on it and nut to lock it all on.

Clutch sprocket, clutch hub, then ?spacer and then lockwasher and nut. All fitted and chain aligns but:

My clutch thrust washer/spacer is a large flat washer around 3-4mm thick. The wsm mentions a dished washer.
Also I cannot understand how the lock washer locks. Its got 2 side flat bits and one longer bit on it. How does it engage in the shaft to allow it to lock?

The engine has been messed with many times before, so cannot assume that the correct bits are present.

Having said that, I have tightened all the nuts up very tight and the clutch operation appears to be fine and appears to work OK.

Shall I leave alone or is there something I have missed?

ps any pics would be useful

[chaz]

have you looked at the Drganfly exploded parts view, sometimes I reference it then do a parts search for sizes and description, still waiting for my cases and crank back before I can check

[JulianS]

The lock washer single tang fits in the hole in the clutch spider.

The lock washer goes between nut and dished washer. Dished washer with recess to outside.

Clean threads with loctite works better than the lock washer, sometimes the single tang will break off when the nut is tightened.

[AdrianS]

Cheers Julian. A bit clearer now. Will take off what I've got and get some new bits!

[Mike Farmer]

 

SRM do a non dished, slightly thicker washer which doesn't "give" in the middle thinner part. Just the washer, threadlock and 70ft/pounds.

Mike

[AdrianS]

I think that's what I've got. I found quite a few SRM bits fitted to the engine when I dismantled it - SRM oil pump, gaskets, sump and filter and now probably the thicker solid clutch spacer. When I dismantled the clutch there was no evidence of a lockwasher but also no evidence of any threadlock as the nut undid relatively easily.
Just ordered the proper bits from Drags so will fit those when they arrive.

[DAVE BRADY]

Hi,

Both of my A65s have the thick washer and I use a bit of thread lock and the correct torque.  I find the 'dished' washer a bit of a puzzle.  The washer is there to hold the clutch centre on the clutch sleeve and there are only the ends of the splines to do this.  With the dished washer fitted as specified with the dish outwards then as the nut is tightened on the thinner part there is the potential for the washer to distort and pressure be slightly taken off the ends of the centre splines on more on to the ends of the sleeve splines.  If it was fitted the other way then the tendency would be to put the pressure evenly on both.  Later clutches, '71 WSM, had a spacer referred to as having a chamfered bore rather than a recess.  It looks like the lock washer was dropped as some point in favour of a lock nut.

Dave.

[JulianS]

The 1970 BSA master price list shows some part supersession;

4 spring spacer 68 3025 shown as "use 68 3169" which is the spacer introduced in 1966 for the 3 spring clutch.

4 spring centre nut 68 3030 shown as "use 68 3320" which is the centre lock nut used from 1967 season for the 3 spring clutch.(the 1966 used a different lock nut which was also superseded by 68 3320)