What size right? Are you talking physical dimensions, power characteristics? Many start out with a small engine displacement entry/beginner level machine then later realize they wish for more. What you need to do is be realistic about what purpose the machine will serve, (ie) will it be used just to run around town, just for an occasional Sunday ride, to travel the highways & by-ways & travel across country. Know what you intend it for then do research to find & purchase an appropriate machine. SIMPLE really..... the right tool for the job! I have owned 29 bikes over my riding career & ridden them all. None is perfect & I wish I could afford more than one & could have kept many. Compromise, choose the most suitable at the given time for the given purpose & you can''t go wrong.

Ron nailed it, also -if you are a lard ass like me you dont want to get a bike with a small C.C. It will have to work too hard to move your fat ass around and will wear out much sooner.I am 275lbs, bonn appetit