Dude!!! I built one of these back ten years ago of so for my kids to race in a 4t kids MX class. I had found a front end off a CR 80 from around 87 iirc that had a disc brake and it bolted right on. I added a KTM 65 shock in a "custom PDS mount on the stock swingarm too. I wish I had a pic of that around...I'll look. One word of advice, Big Gun exhaust makes it as loud as a CRF450f!
Looks like fun.