For the past couple of days I've been experiencing some not so fun behavior from my 91gs500e with 11,000 miles at around 7k rpm. The typical scenario is WOT first gear, everything seems fine, then at 7k the rpms jolt up unexpectedly fast while the bike's speed does not. Shift to 2nd and the bike jerks back into motion with smooth acceleration. I've read about this possibly being the clutch slipping or flat spots. This happens about 2/3 of the time I WOT. I'm not sure what the typical behavior of a flat spot is and/or if a poorly adjusted clutch could cause this problem. Any help appreciated, I'm obviously new to bikes.
change your oil, check that it does NOT say "Friction Modifiers" or "Energy Conservation Formula" on the bottle. <----- neither of those is good for a wet clutch. CHANGE THE OIL AFTER IT'S HOT HOT HOT.
then adjust your clutch properly per the manual.
check your chain adjustment and wheel alignment while you're at it. they're not related to the clutch slipping, but come time for adjustment about the same time. :)