Heh, had the DT50m when I was a youf, pretty much the same bike really, one of the fastest '50cc' bikes in Northampton. Was recorded downhill by a rxs100 at 0ver 70mph. He was flat out too....
Was not what you would call standard mind, looked ordinary but was an absolute bastard to ride with a power band as wide as a politician's conscience.
Loved that bike, I hope it killed the bastard that stole it.