Hate to step on your toes LWC, but KTM ditched the rotax engines in 1985
They went to their own design in 1987 with a limited production run (none in Aust)
then in 1988 they went into full production, I don't think we got many here in Aust
I had one which I rode for the Vic KTM team with Bruce Bolton and Craig Harris. Jim Richards (v8 Supercar fame) also had one
The thing was a weapon, it was a modified one with factory head, cam, pipe and trick bits galore
I had retired from MX the previous year and still trained on a CR500. The first time I rode the thing I was blown away with how powerful and light it was. I had mixed results on it however, being a factory modified production bike it had it's flaws. The very first outing was at the Vic 2 day enduro at "ERICA". I had the fastest special test times overall and had cleared trail time until the last section when I lost drive to discover the rear sprocket had disintergrated leaving 2-3 teeth on each bolt
To add insult to injury the sweep riders in thier wisdom decided not to sweep the last stage thinking that all riders had cleared it!! I had to walk 5km to where the MX pecial test was, to catch the last guy leaving "Phew" I got to the car park at 8.30p.m. Mine was the only one left!! "NOT HAPPY JANICE"