Rotax engine cutaway

Here's a nice cutaway 2 stroke aircooled Rotax engine, Proportion-wise it looks like a snowmobile engine - possibly 250 cc or more but the tag says a bore of 45mm indicating an engine of about 80cc, too big for a weedwacker or chainsaw, too small for a kart or lawnmower. Any guesses?

thanks, Rolf!