I recently examined different engines' crankcases against different sleeves but the inner cuttings in the crankcases around which the sleeves sit in are all different from each other and some sleeves have different length. For sure, my kangaroo's sleeve doesn't fit to my keep on .21. Not to mention the number of ports, but the location of the little notch on top of sleeve in Kangaroo's didn't allow me to set it in the right direction in the crankcase of Keep on.
Maybe some products released in same year share the same crankcase?? Even if so, not sure if sharing sleeves and pistons is possible. For me I just decided not to venture
