We put XR80 forks on my son's CRF70. They raised it quite a bit in the front. I had to get a BBR top clamp to lower them a bit to level the bike out. You will also need a XR80 or XR100 front brake cable. We went with a shock extender (
http://cgi.ebay.com/ebaymotors/Honda...QQcmdZViewItem) with a stiffer spring and it worked great.
He's 9 and loves it. There is a guy here Foxxxxr70 selling XR80 forks in the classified section.
