Originally Posted by generalmyers
Are Number 40 and 41 chains and sprockets the same and isn't number 40 whats used on bicycles now
The are not the same. I don't think anyone has used #40 for bike chain. #410 is very close to bike chain and is what is supplied in some of the newer motor kits. It is noticably narrower than #415 or #41 chain. It probably would fit standard bicycle sprockets but don't quote me on that; I haven't tried it.