Up to 200cc-single or twin 2-stroke air-cooled engine from approved list "
See...that says two stroke...no mention of four strokes...and I've never seen the approved list.
It's kind of a cool class, very specific, just need more people running in it. I'd hate to see it become another "run what you brung" class...even though I like to bump into it. The MT's, TA's and such are real race bikes, nice that they have their own class....just need more people to get them out of the living room and on to the race track.