My son had an OS 70. Nice little engine. Well made. A little heavy for the power output(ours anyway). We have a YS 63 in a 40 sport model. Very powerful, dependable, a little on the heavy side, likes high nitro (20/30%). Personaly, if I was thinking of a Saito 80 I would jump to a Saito 91 or 100. Cost a little more, lots more power. We have two in World Models 40 size Cap 232s and one in a Thunder Tiger 40 size Giles 202. Ours took several tanks of fuel to "break in", lightweight for their power, easy on fuel. Nice engine for the 40-60 size models if you like lots of power to weight. All our little 4-strokes like the OS type F plug. Bob