I just noticed the same thing with my 2012 Speedy. Cruising down the highway today @ 70 mph, I grabbed a handful of throttle and the bike revved up high, with no acceleration. Then it settled down as the clutch engaged and speed went up. Did it in 5th and 4th gears. My Speedy has a grand total of 3200 miles on it. This is not during extreme riding, merely trying to accelerate to pass whilst going down the highway.
