need some help: in order to remove the inner gearbox cover of my mk 3, I have to remove the nuts that holds the casing together (apparently no. 00-0004 in the parts book). However, the nut size is strange: 1/2" socket wont fit (too small) and 9/16" is too loose. They measure 13,5 mm, which would be something like 17/32", but is this the factory size? Can someone confirm this? None of my socket sets includes this size, so I would need to order one, but they seem to be pretty rare...
thanks in advance,
Jan
Hi Jan I haven’t done that…
Hi Jan
I haven’t done that job yet so don’t know for sure, but that size could be 1/4 Whitworth. A good set of Whitworth spanner’s and sockets is worth having for a Commando. cheers
Steve
1/4 whitworth
1/4"whit Is a nominal 13.34mm across flats, so as Gino suggests it may be worth investing in a few sockets or box spanners.
Cycle part wise you should be ok with AF sockets and spanners, but as a Dominator owner I have no idea what was updated inside the motor and gearbox when the Commando came into being.
Good luck!
You don't need many...
... Whitworth spanners - 3/16" BSW / 1/4" BSF, 1/4" BSW / 5/16" BSF and 5/16" BSW / 3/8" BSF will cater for most things. If you get slim 3/8" drive as discussed in another thread they will do you fine.
The Commando gearbox essentially dates back to pre-war days so many of the components have BSF. Whit and Cycle threads.
nuts
are these 5/16 BSC
use a box spanner as very close to edge and a socket may not fit
rgm sell reduced nuts which make the job much easier RGM part number E3231
Definitely 1/4" Whitworth /…
Definitely 1/4" Whitworth / 5/16" BSF (exactly the same size - the hexes were all brought down one step during WW2 to save on material).
I just bought a Sealey 3/8" drive set on eBay 181570393880 £14.77 which fits on those nuts just fine. 1/2" drive might not.
Steve
thanks to everybody for the…
thanks to everybody for the quick help. Actually my sockets are AF ("across flats") and the Whitworth sizes are totally different (shame on me for my ignorance). Will order Whitworth tools today.
Hi I buy a lot of stiff from…
Hi I buy a lot of stiff from RGM but didn't know about the reduced size nuts (and I've just rebuilt my box!
Definitely worth the money since there is very little clearance on one of the nuts.
By the way, everything on the gearbox appears to e cycle thread / whitworth!
One thing I discovered that is not in the manual; it helps if the gear change cam is in the neutral position when fitting the selectors!!
Good luck,
Keith
I'm not sure...
... about those nuts but you can get 5/16" Cycle nuts with reduced hexagons from Nookys Nuts and others. They're used on BSA A10 magnetos if I remember correctly but I find them very handy for monobloc carb studs which have very limited clearance. It also helps to not overtighten them.
There is no need to use…
There is no need to use reduced hex nuts on the MK3, as above the 3/8 drive 1/4 Whit slim wall sockets can easily be found these days.
The reduced hex nuts are OK for the older covers which had a small diameter spot face.
Have you tried 1/4 whitworth? If you dont have whitworth sockets and spanners stop now until you do!