It's definitely off of a SKI-DOO....Measure the BORE and that will narrow down your search quite a bit.
It's a Case reed inducted motor.....which narrows it down further (so it's not a 700 or 800)
Does it have a RAVE valve ?
Try looking on E-bay for a ROTAX cylinder.....you might find the same one and it'll have what it came off of in the Description.
