i've been fighting a fuel starvation, too lean, too rich, something problem that occurs at about 80-90 ish.  i've posted about it and got much help and still working on a cure.  anyway, a friend that also has a gs took his plastics off to paint.  he told me that while they were off and he was at speed, he experienced that bukcing, kinda stalling thing too.  i haven't ridden his bike and he hasn't ridden mine so i don't know if the thing he was describing is exactly the same or not.  does this sound right?  could the plastics off be causing some kind of issue with the air flow to the filter?

I ran into a similar sounding prob. with fouled plugs.  I put one step colder plugs in my bike(a norm for me in cars), but it tuned out that I wasn't ridding hard enough to keep the plugs clean.  I started pushing the bike harder, and it behaved wonderfully, even after miles on open straight roads.  Good Luck

Don