No Sachs or Rotax, his is a very early one (Number 2 in fact) with a factory fitted Falta CZ 380 engine in it. My uncle bought it new from Bill Brown in England back in 1977, then it sat around doing nothing in Scotland for 25 years. My old man went back and retrieved it from a mate back in 2002, crated it up and shipped it to Aus.
I now just ride it (semi)regularly in Vic Classic MX series.
Here's a pic on the VCM site of me on it last year in Evo. Don't let the gratuitous holeshot pic fool you, the clutch blew up getting that start...
