The big thing here is this problem is just the same as the Topic titled "Fair Weather Bike".

This time of year, all kinds of posts pop up where so many think their own bike is doing something strange and unique...

"It was running fine a month ago..."

The problem is in our understanding of an air cooled motorcycle engine.  Gotta forget everything you know about the Honda Accord in your driveway.  This is a Thumper and if it doesn't run right, then CHOKE IT

(And of course, no one reads anyone else's topics.  This is gonna be another "Never Heard Of...")

I suspect that a pin hole might have developed due to deterioration of the vacuum line - but there is another possiblity.

The tank cap is vented - if that cap vent somehow became clogged - the full would not flow down to the carb and the bike would initially run rough and eventually die.

I have never heard of this happenning until last summer when it developed on an RV that I share with my brother. The engine would start, run for 2 second and die - and stay dea - release the gas cap and it would run and stay running

Anyway - just a thought but trying to loosen the gas cap for a second might just be a solution

OK, since we're talking about this; I've had a similar problem as well on a couple of occasions. My bike is a new '08. Each time, my tank was half, or less, full. My question is, could it be due to humidity changes, coupled with temp changes, coupled with the tank filler cap being vented(?), for lack on my part of a better term. I mean, the fuel is hydroscopic. It attracts water, right? This has always occured for me when I've parked it overnight with a less than full tank of gas, and righted itself upon fillup. Filling up the tank would have diluted the watered down gas, reducing or eliminating the problem, right? Or am I totally off the mark. Vacuum leaks would be consistant, I would assume (uh oh). Trash in the tank would declare itself within a realatively short while after each, or nearly each, fillup; but if the problem is only presenting itself with the conditions I described above, then it stands to reason it would be polluted fuel. I readily admit to not being the brightest bulb on the tree, and carburators are not my forte'; however, in trying not to over-think this, it seems reasonable. Please advise. Thanks.