It seemed to make a big difference to me. I dropped 60lbs and my bike (’09 FZ6R) is definitely quicker off the line. There is also a bit of a difference in how quickly I pop back up out of a heavy lean.
I really noticed on my girlfriend’s bike (a little Suzuki s40 or savage ls650, same thing) that it was a little quicker and more highway worthy without hauling an extra tub of blubber around, as it seemed to gain a few extra mph. Then again I still look a little silly at 6’5″ on that with my knees up above the tank.
I’m sure it will make a difference in my fuel efficiency and I look forward to that on some of my long trips I have planned for the summer.
So how did you lose the weight? My gf kicked my butt into joining weight watchers with her and it really did work well for us.