This type of engine has just one cylinder and will work best on modest cc bikes. It really is cheap to keep up and take care of if a thing goes wrong. Additionally, it generates high torque at small revs, which makes it appropriate for off-highway and commuter bikes. Example: https://trentonhcumb.boyblogguide.com/34059670/the-best-side-of-what-are-all-sizes-of-2-stroke-bike-engines