It's fuel delivery related. Check the entire fuel delivery process from vents to all carb parts. Remove the carb and check everything. Record everything including all jet sizes, mix turns, etc. Ever since this started I keep thinking the vent is plugged (miacycles suggestion).
This happened to me several times motorcycle racing and with street bikes. The symtoms were identical, except I immediately checked my gas and noticed a sucking for air sound when I opened the cap. Presto, on the road again all times!
If not fuel delivery, it is your module. My 2 cents!

 

Just back from a 322 km trip ( one way ) back home again around 800 km.
( 500 miles ) and I was stranded on the first 80 miles on the road.
Coughing..slowing down..running again for a few miles..then final death.
Cellphone..road assistance..towed away to the next gasstation.
Filled it up 8 litres ( 2 gallons used ) 125 km on the clock.
Started up fine..good idle..off I go..next 2 gallons used same behavior..
Lucky sputtered in front of another fill up..really lucky since the engine died
on the spot a meter away from the gas pump.
Since then I filled it up every 100 km ( 65 miles ) which is crazy but it worked
The whole trip no more probs and running fine ( apart from coughing ).
So..I can't come to no other conclusion ..its starving for GAS.
Now..how do you explain that?

 

Probably not your issue, but stay away from the enricher **** as much as possible. You want to pull it open just enough so that you can start the bike and then push it back in as far as possible where it will still run and keep the bike running using the throttle. After a minute or so, you should be able to push it in the rest of the way. If the carb is jetted right and the temperature is above 70, you should probably just have to start the bike with the **** half way out and then immediately push it in. Too much use of the enricher **** will foul the plugs all the time.

 

It's not the plugs or the choke.
It's more than that.
As far as I can see it's lousy behavior on a expensive bike.
Never experienced on many metric bikes I owned.
How to trust this bike?
Back to Japanese bikes for half the price and flawless performance?
Maybe I will.

 

these old bikes are built pretty simple. if its the fuel system then start with the gastank,clean the petcock screen,check petcock fuel flow,then gas lines to the carb and finaly take the carb off and clean it compleaty. could even be somthing as simple as a bad gas caps not venting. ona metric id be totaly lost ive seen how those are put together!
dont give up man i know it can be frustrating. once you find it your bike s.be pretty reliable after all its an evo!

 

clean your fuel petcock. its probably gunked up at the bottom of the screen.

 

Easy to explain, maybe your petcock screen is pluged up, remove it and see, I had mine plug up, no big deal.

 

Guys,

If it starts and runs after filling or setting it has a partially plugged vent tube.

Each time you allow the air to enter the tank, either when fueling, or after setting so it can slowly draw air into the tank, through a partially plugged vent hose, it would start and run until the vacuum gets so strong it will not allow gas to flow out of the tank.

Imagine taking 2 gallons of gas out of your tank without it venting correctly. It builds such a strong vacuum the gas will not flow to the carb.

Mine was clogged at the very end which sticks out under the motor near the ground. Mine had chunky bug parts clogging it AND the hose was so old and soft it cold easily collapse, or be pinched closed.

It's a simple task to uncover the top of the tank and locate the hose. I replaced mine with a fuel line quality hose. The original hose is more like windshield washer hose in cars.

 

While I agree that a clogged vent hose causes sputtering it takes far less than 2 gallons it takes about 2 miles (at least on my '95 FLSTC). I recently had the plugged vent hose that is why I know it doesn't take 2 gallons. My bet is on the clogged screen on the petcock.

 

The main way you can tell if it is a plugged vent hose is if you get a rush of air entering the tank when you pull the gas cap off.