I have removed the primary cover to try and stop a leak (small) and noticed that the one of the casting areas around the one of the bolt holes is machined away , is this normal , as this could be the reason as the oil would run out beside the bolt unless a rubber seal is used at the base of the bolt head
probably due to a worn chain flapping around and sawing its way into the casting, have you a picture?
If I remember correctly one of the bottom bolts is machined away this is the bolt that you take out to drain the oil out there is another one which gives you the correct oil level both these bolts should have a fibre washer behind the head.
I managed to source cork gaskets a few years ago, did the job. You can also obtain small o-rings that fit tight over the screws, they also help when you get a weep through the threads.
thank you , I did think it may be for draining the crankcase oil after giving it a little more thought , and also using a small o ring to seal it, although a fibre washer sounds a better idea
Hi,
BSA originally used alloy washers part number 40-0740 on the drain and level case screws.
Best wishes...