that bike is nice. i think you stole that bike for 1200 bucks, wow. i have a 125 and idk. i dont really think the 250's are heavy. i put it up with both wheels off the ground no problem.
like joe said though, i have been just putting along and just slightly touched the throttle and it jumped up and went. the way you said the owner never did anything to it since he owned it i picture it as a neglected junker, it looks good though. i wonder what inside looks like. the reason i recommended the the bigger bike was that, i dont see the point in spending cash on a bike because you need more power and you dont wanna by a bigger bike because they weigh a few more pounds. but, thats me. like joe basically said, everyone is different and has there own personal prefrences. anyway, good luck the bike looks real clean. take good care of it and it will stay that way....