RE: New OS FSa-56 4 stroke
Oh, doesn't this engine really look like a 'four-stroke AX'?
...The extended cylinder cooling fins are partly shrouding the push-rod guide tubes...
And that avatar sure looks familar... I'm sure I have seen it somewhere before...
And speaking of old OS FSR engines, many people think they run better than most new offerings; even from OS... They sure last longer.