I bought my R90S 33 odd years ago and I'm finally got the time to do a restoration back to its original Daytona orange and silver. When I bought the bike, it was crashed several times by the previous owners and didn't have the original paint or fairing. It had a nasty looking Luftmeister fairing and was painted black. I ditched the Luftmeister a long time ago and made it a standard motorcycle.
The bike is generally in good mechanical shape except it needs the 2nd oversize pistons. I had a KN airfilter and it eventually got hard and stiff and didn't seal and dirt got thru and wiped out the cylinders cross hatching and it now burns oil and smokes.
I rebuilt the motor with new mains a decade ago. I had the tranny open when I was in college and put in a shift kit and new tranny bearings. I had Brown Motorworks in Pamona rebuild the final drive. I had the flywheel lightened when I did the engine.
Years ago I rode a friend's R80GS and noticed his bike runs significantly smoother. Like glass and I'd like to make my R90S run as smooth as the R80 if possible.
There really isn't much I can do except to buy lighter parts and there is a place that sells them.
Motoren Israel is a shop in Germany that specializes in airheads and I already need pistons, I'm considering adding connecting rods to my list.
They sell Wossner pistons and claim they are 190g lighter than stock (516g/712g).
They also had H beam rods and say they are 450g and stocks are 600g.
https://www.motoren-israel.com/
anyone think the rods are worth the extra $800?
If anyone has rode a R80GS or RT or ST should know how smooth those engines are.
Its about 1.5 pounds of reciprocating mass reduction. It almost seems too good to be true but the original parts were designed 50 years ago.