Honda Stopped making the CR500 in the mid nintes(it had not changed for years).Service Honda has a deal with the Honda factory to get CR500 motors and put them in CRF frames.They have been doing this for quite some time and they ran about 10k.Now there are offering upgraded models.I had a buddy who raced 500 pro years ago and most tracks were 3rd gear.What I mean by that is start off the line in 3rd and never shift the whole race!!