Busted flywheel key can cause this, or something messed up in the ignition module. Two-strokes work just as well in both directions. There was an old boat motor like that... You kill the motor, flip a switch to change the timing, start it up and you're in reverse...
Black 85 Spree-SOLD
Red 87 Spree... Ended up buying the same one mentioned below.
I started riding my uncle's 87 Spree at the drag strip when I was 8...
It's easier to stop caring three years ago than it is to fix it in present time.
I had a dirt bike that would run backwards, a 1972 Yamaha MX 100.
But it used piston port induction and contact breaker points type ignition.
2-cycle engines with a reed valve induction and/or electronic ign. will not run backwards