not firing on one cyl

[johnr]

if the bikes only ever been started on the stand and run then shut down since you built it, its not unusual for it to foul plugs. when you fire it up, take it out for a run and thrash it a bit to clear its throat!

[fossie]

It is possible that sediment would end up in that carb especially on those twin choke jobbies.
Removing the bulb won't have any affect ,if the switch is missing on that type the bulb will only show when the ignition is switched on as a check.