Trying to ride a cr500

You realize that the CR500 isn't made anymore, right?

Other than that, the difference between a 2-stroke 500 and a 4-stroke 450 isn't huge. The 500 will hit a lot harder and is much less linear in power delivery. Yes, you can lug a 500 (be lazy) and get away with it, but for most newer riders, it's a lot easier to go faster on a 4-stroke.

Unless you find an CR500AF ( a 500cc 2-stroke in a newer aluminum crf250 frame, big $$), the 500 you'll own will be a old-school steel framed bike. Advances in frame material and geometry along with superior suspension of the newer bikes will more than make up for a few horsepower difference.