Kinda sounds like what was happening to my bike before the clutch went out. I dunno, my RPM's were jumping then lagging, as if the bike was getting no throttle. I rode the bike 50 more miles to the point where it got throttle up to 8k rpms in 3rd gear and wouldn't go over 70 mph. Then it stopped going over 17 mph. Just something to look at, I dunno though. It sounds like a fuel problem but so did mine at first. Maybe it's because of the RPM jump, and seemingly loss of fuel flow to the engine. I guess you'll find out if you keep riding it and the clutch stops working.