I was on my usual Sunday ride this morning and had a weird thing happen...

I was doing about 65 on the freeway in a slight rain, applied the throttle to pass a car and the engine stumbled...it momentarily wouldn't take the throttle and acted as if it was running out of gas (I had just filled the tank)...or like there was a vacuum leak...after a minute or so, it cleared itself and ran fine all the way home...the incident had me instinctively thinking about switching the petcock to reserve, like in the old days...

Any insight into what caused this?

 

If you had just filled it there is the possiblity you had a vapor lock condition that somehow worked itself out... other members on here have had this happen (I have not yet experienced) Usually opening the fuel fill to release the vacuum fixes it.

 

okay, tks...really, strange, as it's the first time I've experienced it in the 5+ years I've had the bike...

 

You either have:

A: a tank vacuum lock for overfilling the tank but this usually happens within less than a mile from the station or
B: the tank vacuum line located at the bottom of engine behind the lower cowl ingested some water from the rain causing the same vacuum lock or
C: ingested some water in the front cylinder spark plug wire causing a misfire.