i need to buy a new bike and i was thinking a cr250, rm250 , kx500, or some four stroke. im replacing my 89 kdx 200 and i like the power i want more of the snap and acceleration though. i was thinking 500 as they are cheap. would the power be to much for a 15 year old 200lb 6' rider? also would the big bike go through too much gas, sprockets , tires , etc ? oh all the bikes would be early 90's and if you have advice please let me know .