Hi folks, I posted this query on the AOMCC forum but am a bit uneasy with the reply, so would appreciate another opinion:
I bought a 23 tooth sprocket to replace the 19 tooth one on my 1950 VB; but having dissembled the primary side, I find that the lobe profile is not the same, so it doesn't match up with the shock absorber/sliding member. The lobes are different widths and have a different curvature - the load bearing surface would be much less. I gather the 23 tooth sprocket is probably for an earlier (pre 1945 Ariel).
My question is: am I safe to fit this on or not ? I've been told - yes, people have done this, but I'm concerned. There is very little contact surface so it will wear rapidly - but is it likely to be able to perform correctly and transmit the engine power safely ?
Or should I admit I stuffed up and get a suitable sprocket made ?
I hadn't seen your AOMCC post until just now but you'd be well advised to ignore what you read there. The attached photograph is of the two pieces of a 19T sprocket I bought for my 1928 Ariel, which looks very much like one of yours. The problem was just the sprocket itself originally came and it doesn't match the cam I already have with the 23T on my bike, which looks like the other one of yours. Once I discovered the problem I was able to buy the mating cam as well as the spring, which also is different. .
Anyway, there seem to be early (as in pre-'29) and late (as in '29 through at least the time of yours) sprocket assemblies. Mis-mating sprockets and cams is the wrong thing to do.