Odd thing happened yesterday (fueling)
 

I rode from london to brighton yesterday. Bike has been unused for about a week (snow...) but started up ok (took a few seconds on the button), and rode fine through london itself. When I joined the motorway, it was ok, but after being at motorway speeds for about 20 or 30 mins, the engine starting to become ver unresponsive to throttle openings - it felt like it was restricted again. Opening the throttle in 5th gear at 70 mph (so about 6000 rpm) the bike hesitated, like it wasnt getting enough fuel. Could this simply be some carb icing going on? when I got to brighton, and slowed down again to town speeds, the engine was again responsive. I don;t use any PRO FST because I find V-power usually is good enough, but perhaps the col weather, high humidity and high speeds at reasonably constant rpm could have caused some carb icing?

is there anything else I could be loking at? Spark plugs are about 3000 miles old, air filter is quite clean and there is no obvious obstructions.

Re: Odd thing happened yesterday (fueling)
 

Yep carb icing I think. Mines done exactly the same thing a few times in just those circumstances, coldish day , high humidity and a fairly constant throttle setting for a while. Soon as you slow down a bit or stop hot motor warms everything up and problem gone .

Re: Odd thing happened yesterday (fueling)
 

Agree with gms, sounds like carb icing or possibly damp on the plug?, had similar myself but after waterproofing the front plug and filling with super never reoccured.