Your choice, my friend.
Back in the day, not many builders ran pocket bike engines. I still have a 10hp(cough cough) modified pb engine I bought on ebay for cheap. It quit running on its maiden voyage. It coulda been loose studs. Strangely, there is no keyway on the crank, so unsure if timing is off. I also have a stock pb engine I bought years ago; it just needs a pullstart.
I like pb engines; they are so compact, once you lose the 3:1 gearbox.