I found this site looking for information on KX500AF conversions. I just completed building one from a 2007 KX250f chassis and a 99 KX500 motor. I also have a 2005 KX250f, a 1994 KX250, a 1995 KLX650 used for dual sport. Also a 1989 ATK406 and 2005 KTM 450SX with electric start and 6 speed conversions. I also have my own shop in Glendale, AZ that does off-road race prep and complete repair service.