Decided to start the RVFlette today after a few weeks of sitting since balancing the carbs. Last time, it ran great. Today, I went to start it, and it didn't want to run.

Pull the choke, hit the starter, and the bike catches quickly. It'll "kick" up to about 2k RPM, and then drop to about 1k, and then die after about 5-6 seconds. It's running strongly when it is running, but it just won't stay alive. Feeding it any throttle at all causes it to die.

I plan to dig into it tomorrow morning, but any suggestions on where to start?

Vacuum pipe from the fuel tap either not connected 100% or perished and is collapsing so stopping fuel flow. Or possibly a kinked fuel hose, whip the tank off and have a quick check in them!