having an un-ported cub myself I can tell you it runs hard no matter which way you look at it and you have lots of room to expand and improve on it. that being said i have been beaten by 2 and possibly a 3rd stock cylinder bikes (to the best of my knowledge) one of them was resleeved to a 68 bore same size as a cub and he just beat me by a a small amount maybe 2 bikes at the top of the hill. (i hillshoot) then the other two bikes beat the crap out of me but one was a full out drag bike, the other which i was told was a stock cylinder by a third person so im not positive, was just damn fast. but when i port mine this winter you can be damn sure i will race those bikes again and hand them their ass.