Weird surge letting off throttle.

Okay as i think about this I get more and more confused. When I go to pass a cage on the highway, or do a high speed blast. As I'm letting off the throttle at some point, not sure when, the bike will give a surge foward like I gave a blip of the throttle. But no blip. It's almost as if the clutch is suddenly grabbing,or the ignition timing is suddenly/temporarily advancing,or the carbs just plain acting weird. It's smooth accelerating to the top end in all the gears,just happens when I let off. Also, my top gear r.p.m.'s only hit about 8200.The motor appears to be in good shape, no smoke hot or cold. Kinda confused at the backing off surge, any help would be appericiated. Thanks
Ray.