Also, kind of funny story on why I have the '78 RM......
I started into MX in the 80's, so I never had a dual shock bike. I had never even ridden one.
At one point I decided I wanted to have an RM from each decade....70's, 80's, 90's, etc.
Obviously I have the 80's pretty well covered....and I also have a current bike and a '92 RM125 that needs put back together.
So...I needed a 70's bike. Ran across that 1978 owned by a friend, and it seemed like the perfect fit! First time I rode it was when I went to the AHRMA National at Gatorback Feb 2010. I raced it in the Cross Country and got 2nd on it! Then in MX I broke the right footpeg.
Bike is very cool and definitely very different to ride.