When I was a teenager my brother and I had wore out a couple kx400's and we bought brand new 420's the first year that they came out with a single rear shock. We rode them all over. Two years ago my youngest son want to buy a dirt blike, he was 19. I hadn't been near one since I was his age. I found a kdx420 and a kx420 for $300 each and rode them about a year. We couldn't get very far away from the truck due to breakdowns. I learned a lot about how to fix things out in the desert and I have learned a lot from this site. We sold the 420's and now ride 500's a 98 and a 2000. We ride with my brother and a friend both who ride 500's. We like single track trails and I really like to ride out in the open. I can leave my house and ride 80 miles out in the desert which is sage brush hills and bluffs without going on a road. We ride all year round which means snow and 25 degrees in the winter. I bought the first 500 in April and last week I put on the 5th new back tire. We have a place we call the badlands which are clay hills that you can go climb in. It is very fun and the 500's are perfect for them.
I have attached a couple of pictures.