Having a new problem with my 08 - was cruising down the highway last week when the engine cut out on me. Figuring it was just low, I switched to reserve, but the bike refused to run right. I just spent all of today cleaning and rebuilding and synchronizing the carbs, which was a great learning experience, but it seems to have gotten me nowhere.
Symptoms:
When cold or warm, it will only start with full choke
With full choke, it switches between running at 1500 or around 4000 RPM.
With full choke, as soon as I touch the throttle it bogs down and dies
With choke off, it dies immediately, even when warm.
I added a gallon of gas to dilute the seafoam I had tried, and voila, after about a minute it picked right up and ran great. But after I rode around for a while and burned up that gallon or so, it cut out again.
Thoughs? My other idea had been a clogged line or something, but I blasted everything out with compressed air while it was apart today. It also behaves the same with the petcock at on or reserve.
I'd be looking at the fuel tap Vacuum system for a start. Try running it on prime and see if it still cuts out.