Help! BSA A7SS Clutch Centre Nut.

Can anyone suggest the best method for undoing the centre retaining
bolt in a 1960 6 spring BSA A7SS Clutch.

I have the Gearbox out of the frame on the bench - which was not easy
with the clutch and final drive back plate still attached as it made
it impossible to remove some of the mounting bolts!

The Haynes manual says to "Scotch" the clutch centre and undo the nut.
I've since found out that "Scotch" means jam it with something! But
I'm not sure how to do that without damaging the clutch plate fingers
or spring threaded studs.

Operating the kick start spins the clutch centre anti clockwise, so I
assume the nut needs to be turned anticlockwise to undo it?

Thanks for any suggestions.

Phil Newsome
Honda VTR1000 SP2
BSA A7SS (Soon!)

 

I think the idea is that you undo the nut while the gearbox is still in the
frame , if you put something to lock the clutch ( an old inner and outer
plate bolted together for example , or a little metal strut) and then press
the back brake you can then get some purchase to undo the nut, otherwise it
just turns round on its shaft, also theres probably a locking tab up the
side somewhere. Maybe put some chain round the sprocket and fasten that in
the vice to lock it up. The nut is pretty tight approx 60 ft lb.
steve the grease

 

What Chap says, plus I have successfully done something similar using an
ordinary impact driver instead of a pneumatic one.

 

Success - Thanks for all the suggestions.

Compressor and Impact Wrench would be nice - I'll have to put it on my
birthday list!

The successfull method was to put the clutch plates back in and clamp
them carefully front to back with a pair of cramps.

Some sort of Tab washer might be a good idea so I don't have to re
tighten it too much when re building. It has obviously worked loose in
the past by the evidence of the round scrape marks on the inside of
the primary drive cover plate!

Phil Newsome
Honda VTR1000 SP2
BSA A7SS (Soon!)