They're a great bike,good torque. Not too easy to find complete either. If you keep your eye on E Bay parts pop up,,ppl parting out a complete bike.
If you got enough of the tank left you could always repair & repaint. When you search them,I've found them under both Rockford Chibi & Bridgestone Chibi.
I bought one from a neighbor back in '74 after he bent the forks crashing in a ditch...$15 haha I used it to power a go kart I was laying out. Used the tires & rims on the back of the kart ,,kept the brake controls separate . Man could you spin out in the cinders on asphalt , just grab one brake lever and hold on !! That little engine pushed that kart to 43mph Those were the days hehehe