Heres a shot on my 1976 R90/6 in 1985 at the Delaware Water Gap ,a few days after buying it and heading out from Va Beach to Canada:
Same bike a couple of years later at a rally in NC.
Here it is about three years ago after a little work:
As far as I'm concerned, the R90s represent one of the true high points of Airhead development because the guys in Germany got so many things rght. Good power, good fuel economy, pretty smooth and there are plenty of things that you can do to make em runn good and last.
PS: My old R90 engine just loved
to cruise at 80 to 85 MPH and would returm 40 or more MPG. These days my bike is equiped with an R100 engine and I like it but the R90 was very special! I'm glad that you shucked that fairing but if you decide to swap seats, make sure you keep that double bucket. Theyre great for long distance riding.
Take care of Grandpa's bike. You'll love it!!