I have a set I got for my son when he was 2 1/2 and started riding his KDX50 (he rides a KLX110 now). I'll snap some pics, just note, DO NOT make the ones that connect to the rear wheel like a bicycle, they are not stable, make the type that connect under the belly of the bike to the foot pegs. We would beat the snot out of that bike and never tipped it.
Baiscally it is a bent bar that has a set of brackets in the middle, the brackets connect to the foot pegs via longer bolts and then on the end are a set of wheels. You can get them all made for your bike for less than $100 on ebay, may be worth just buying some that you know are tried and true rather than risking making something you are unsure of?
Last edited by marc11; 09-23-2009 at 11:55 AM.