Ok. I'm stumped. Here's the story: '05. 4k+ miles. Bone stock mechanically. Over maintained. Sat up for 6weeks+ because of back injury (mine - not bikes's). Cranked and idled a few minutes every week or so.
Two weeks ago took out to ride. Pooped around the neighborhood for a few minutes then out on a big road using moderate acceleration. Got a miss or two then rough run, so I headed home. Died about 100yds from house. Told envious neighbors that bike was fine, I just need the exercise of pushing it. Got in driveway, bike cranked and idled about 30 seconds then died sharply (not like fuel starvation). Did that a couple of times.

Here's what I've done. Drained, removed and rinsed tank. Removed, disassembled and cleaned petcock (it and screens appeared clean). Reinstalled. Petcock vacuum diaphragm held 10ins vacuum for over 3 minutes. Replaced tank and put on new hoses. 1 gallon of fresh gas with 4oz Berryman (same as Seafoam). Drained float bowl until fresh gas flowed. Cranked and ran 30 seconds or so til it died. Let stand overnight.

Cranked and got same thing - run a short time then quick die, might restart and run for a few seconds. Removed carb. Float bowl sparkly clean. No binding of float, float valve OK. Removed pilot mixture screw, cleaned seat and reassembled @1 /1/2 turns (original setting was 1 3/8). Removed, cleaned and replaced main jet assembly, removed, cleaned and replaced pilot jet. All jet bores were soaked with carb cleaner and blown out with 40lbs air.

I did not remove the air cutoff assembly or the diaphragm and slide assembly.

Same results. Will not run at idle. Will run with choke or 2k rpm throttle for 30 seconds or so and then abrupt die. Fuel flows freely thru float bowl when vacuum applied to petcock and float bowl drain opened so no float or float valve problems indicated.

Forgot to mention, tank vent and hose are clear. Even dies with the fuel cap open.

I've tried to avoid a complete teardown and soak cause of my poor vision -- it's very difficult to work with the small parts and if something is dropped it's a major problem (I actually pull the needles and stuff inside a large clear plastic bag!! so as not to lose them if they drop).

Hopefully, I'm overlooking something simple. What do you think???

WOW, you've been perfectly thourough with the carb, have you considered an electrical issue? Wire rubbed thru and grounding somewhere. Possibly kill switch gone bad? What about your Kickstand and clutch safeties? Are they bypasses? I am just throwing some bones here while I mull it over some more.

Yeah, I guess that's my next shot. I'll put a spark tester on and see if it's making spark when it's cranking after it dies. Thought maybe a component was failing with heat, but it's really not running long enough to get hot.

It'll be a couple of days before I can get back on it, so that'll let the solvent get a good workout. I just can't imagine it being anything but somewhere in the fuel system.

I'll appreciate ANY other ideas, no matter what.

This sounds like nearly the same issue some of the '08s are having. Electrical under the tank areas are rubbed the wrong way.

Thanks. Keep'em coming.

Les, your post reminds me of a Jon Lovitz line - "I used to date a massage therapist, but we broke up. She just rubbed me the wrong way."

it sound like the fuel system is ok I would have to lean to electical I have seen coils and electronic ignitions do this all thow it is rare but posible the componets work but heat up internaly breaking the conections down. is it posible your wires coming out of your stater housing may have been rubbed by your sprocket.

Update. Had a few minutes to mess with bike.

I pulled and cleaned slide/diaphragm - was clean and no apparent flaws in rubber. Pulled and rechecked assembly of pilot mixture screw and reset at two turns.

It is not electrical. After it dies it still makes spark while cranking.

Got the KLX choke assembly from local dealer. Since I didn't need to order anything else, it was cheaper than getting it online (like $23 OTD). Very simple install. It's more complicated to reach when on bike but that will get better with experience. It does allow you to rotate the carb without worrying about breaking the cable fitting.

I do think I'll go back to the factory handlebar choke when I get this problem sorted out -- it's just way more convenient. I've got one of the metal fittings ordered from Stead. That and disconnecting the cable at the handlebar lever (quick and easy) should allow carb work with little risk of damage.

I think now I'll take the carb completely down and do an overnight soak. If a complete cleanup doesn't help, I'll probably involve a pro (if I can find one). I prefer not to use the dealer.

I'll get back on it in a couple of days and advise.

Very interesting! You said it dies quite quickly, fuel usually flutters out, I know you said it has spark after it dies but how good is the spark? A weak spark can mean no start. I'd be looking for an electrical issue. Wish I could drop in and have a peek.

Yep, I continue to be puzzled. Don't know the strength of spark (verified spark with inductiion timing light).

I'm sure it will turn out to be simple. Just something I overlooked first time. Thanks.

edit - actually, I may have hit that "dies quickly" thing too hard. When cranked cold and run on choke or throttle (2-3k rpm) it will die sharply after maybe a minute. Then when cranked immediately after, it may run a few seconds, miss a little and then die - exactly what you'd expect from fuel problem.

Reason tells me it is running the float bowl dry. But everything I've done indicates that gas is flowing into the float bowl correctly. Makin' me crazy.

May I suggest a fesh spark plug? cranking and idling for a few minutes several times may have fouled the plug.
just a thought
good luck