there are a couple on this board that can and do. And yes if you start on a bike thats too big your learning curve won't be a curve, it'll be a straight flat line. Basically anyone who's ridden a 250 for 6 mos. could theoretically beat someone who's only ridden a litre bike since day one. It's sad when the newbies with the best bike on the market get beat by a guy(or gal) on a 10 yr. old 600, sad for the newbie.