I agree with Bill and his reasoning on choosing the 50cc or in the case of the Taurus, 52cc over the 2,4 0r 40. I wouldn't even consider a 40cc with only a few onces difference in weight, but quite a bit more power when you do move up. Makes since to buy a bigger engine now that's a little overkill for the application you need right now, than have to spend more money to buy a bigger engine in the future.