You might also consider a lighter oil. Those bikes originally came with 5 weight. A lot of people have gone to 7.5 for road use. Some have gone heavier for racing. I tried the Motul 10W in my 82 R100 and did not like the feel of it. Went to 7.5 and it is much smoother. At least to me.
Heavier oil can cause seals to weep or leak if ridden aggressively.
I would also recheck the installation of those seals.