Motorcycle Repair: Gas kills the engine., honda v45 magna, 1983 honda v45 magna

Question
I have a 1983 Honda V45 Magna with 21,000 kms on it. It has been parked in the garage for 2 years.  It starts easily with full choke, but even after warming up when I reduce the choke or throttle even slightly, it kills the engine immediately. Battery is fully charged, and new gas in tank. Any thoughts?  

Answer
Kirk,
very likely the idle and possibly other jets
are plugged from sitting so long. The gas
turns into gel and then a white crusty varnish
that plugs carb jets.
It may have plugged the fuel tap/valve in the tank
as well, though it sounds like you have some gas
in the carbs. The float needle/valves could be
stuck or varnished also.
You may have to clean the carbs.
When you open the throttle, you are allowing more
intake of air, without enough fuel to add to this,
the engine stalls.