AJS & Matchless Owners Club

Nice one - and 1/2 in drive too.

Looking again at this with calculator in hand, a 38 might actually go on, but a 1 1/2"AF is the sure-fire fit, and, if it turns out that the 'correct' CP nut IS in fact 1.5", then the tool is there for doing it back up tight! These nuts can be a pain because they're shallow relative to width and chamfered as well usually on the points, so a decent fit is a big help.

Thank you to all who replied. The six sided 38 mm socket that I bought fitted perfectly with a few thou to spare. Anyway the nut is now off. Surprisingly it was not on very tight at all. Clearly a PO did not have the correct socket to put it back on and probably just tapped it round with a hammer before bending over the locking washer. Now to remove the rest of the engine and split the crank cases.