Prepare to be surprised then...this is a COMMOM VENT problem! most always caused by the vent hose (that exits down the frame in front of the rear tire) getting "blocked" by water as it sprays up ...difficult to simulate with a "hose" or on a dry day! once the vent hose is blocked or pinched, it's like tring to pour gas out of a gas can without opening the vent...you'll get that 'glug-glug-glug' as it burps in air...however your poor little fule line can't burp in as quickly as your gas can can...hence the sputter-stall-die...wait a few an it starts again...air burped in and bowls refilled... it can also happen even WITH the "vented gas cap" (if its raining hard enough...but is SIGNIFICANTLY reduced)...change your cap and CUT the vent hose in front of the rear tire at a sharp angle (increasing the "hole" size of the tube...the Cylinder you refer to "under the air box" is only on bikes set up for CA emissions...
If you've been fortunate enough to put 22K on your bike without ever having this happen you are very fortunate indeed...most everyone else has had this happen...(and as a precaution grease the snot out of all of your ele. connections with dielectric grease
