This sort of engine has only one cylinder and will work best on little cc bikes. It's cheap to keep up and take care of if something goes Completely wrong. It also provides high torque at minimal revs, which makes it ideal for off-street and commuter bikes. Example: Splendor, Platina https://mylesapdvk.dgbloggers.com/35531518/detailed-notes-on-pocket-bike-racing-engines