This sort of engine has just one cylinder and is effective best on small cc bikes. It is cheap to take care of and fix if some thing goes wrong. It also makes high torque at lower revs, which makes it appropriate for off-road and commuter bikes. Example: Splendor, Platina https://bike-engines48024.amoblog.com/the-best-side-of-bike-engines-for-sale-56917985