Motorcycle Repair: 1980 yamaha1100 xs, vacuum line, air vent

Question
My bike will be running good but then at times it seems to lose its power and i'll
have to pull over and wait five minutes then it will run good then the same thing
will happen.  What do you think the problem could be

Answer
Aaron,

I think it may be having trouble
with the fuel supply.
-The fuel tank air vent could be plugged which prevents fuel flow.
-The fuel petcock valve rubbers may be cracked or hardened.
-The fuel valve has a vacuum line from the engine
that allows it to open and supply fuel to the
carbs when running.
-Also the fuel valve in the gas tank
has a screen up inside the tank which may plug up.

I think if you examine the fuel system from
the tank to the carbs you will find the problem.
If it has a fuel filter check that as well.

There is a chance that some ignition component
could be cutting out when warm.
If it quits on you quickly check if it has
spark or not. Just carry a spare spark plug
with you and stick it in any plug wire
and lay it on the engine.
If it has spark then the problem is likely the fuel system.
If it has no spark, write back for more info.