Main bearing circlip
The original circlip (65-2240) that holds the outer left hand main bearing in
place is about impossible to refit without putting aluminum shavings into
the bearing. Go to your local bearing supplier with the crankcase and the old circlip
and ask for a modern circlip of the same size (the type
with an eyelet in each end) and buy a decent set of circlip pliers to
suit. You might need to linish the outer edge of the circlip slightly to
fit in the existing narrow slot, but it can then be fitted & removed
with no further problems.
Use a 54mm diameter external circlip. (i.e. to fit a 54mm bore). It is actually around 57 mm external diameter as bought, to allow it to be compressed & subsequently sprung into place in the machined groove in the crankcase. These are 2mm wide. (About 0.080 inch). They can be purchased at any bearing supply specialist for a very modest price.
The original BSA circlip is 1/16 inch wide. i.e. 0.0625 thou or around 1.5mm; so the new item will need to be reduced in thickness to match the original. This is easily done on a linishing (or sanding) belt in about 5 minutes.
Using a suitable pair of circlip pliers, it is very easy to fit/remove the new circlip without contaminating the open side of the new bearing with aluminium slivers or debris, which certainly is not the case with the original BSA item.
|BSA WDM20 Reference Material|
|G’day folks:- My name is Mike Jeremy; I live in Cairns,
Australia. I’ve run a 1953 M20 for 20 + years & am slowly restoring a totally worn-out 1941/42 WM20. Henk’s web-site has been a great help with the
latter. I am secretary of the local motorcycle restorers club & part of that task is to be custodian of a well – indexed library of several hundred U.K. ‘Classic Bike’ & ‘Classic Motorcycle’ magazines, that is essentially complete from the present time back to around 1981. (Plus a few other titles as
shown). During the rebuild of my WM20 I have checked through these magazines & as a result, listed below are articles that relate directly or generally to the WM20/M20 range & could be useful to other owners. There may well be errors &