Motorcycle Repair: Carburetor Honda 1983 550CB Nighthawk, rubber diaphragm, pasages

Question
I just bought the bike which was in the garage for approx, 8 years.
I cleaned the fuel tank, checked for spark and had it started but did not idle well. Number cylinder did have spark but was not firing (so ment no fuel).
I cleaned the carburetors (4 of them) and cleaned the 2 orifices for medium and high speed. Also checked the vaccum   diafragms and seemed okay ( did not check the orifices for the air pasages at the time.
When I started again now number one cylinder fires okay and it seems to idle better. But when I open the throtle to medium or high it dies (appears as starvation of fuel) anf if I keep the throtle open dies down to stop, howver if I close the throtle it goes to idle okay.
I noticed that the pistons in the carburator do not go up whe I open the throtle, which should to open more the passage for air and also the taper needlo to allow more fuel to the engine.
I do not know where the passages go or what it could be, It is unusual that the 4 carburators do exactle the same thing.
Any sugestions?
I am in a remote area and do not have compressed air to blow into the holes. Any diagram that I can see for the detailed operation of the pistons relating to speed or air flow into the engine.
Thanks, Wilson
Burk's Falls, Ontario

Answer
Wilson,

Glad you found the problem, the original
factory manuals may be available from
http://www.helminc.com/helm/about_assist.asp?Style=&mscsid=MASLFET8WT309P572H6VR...


-when you have a problem that affects all the carburetors
you have to look at whats common to them all.
-The common part here would be your fuel petcock.
-The petcock or fuel valve is operated
with vacuum from the engine and has a little
rubber diaphragm that is likely faulty
after sitting so many years.
-At idle the vacuum is high so it probably
gets some fuel, as the engine speeds up the
vacuum is lower and the petcock is not
opening enough to provide fuel.
-Did you remove the petcock from the tank
and clean/check it out?
It also has a filter up inside the tank.
-Double check your fuel supply and
fuel lines for blockage.