Motorcycle Repair: Honda cx 500, honda cx 500, 1981 honda cx500

Question
My 1981 Honda CX500 seems to be running out of fuel. carbs are dry but the tank is full. This bike has sat for many years.have run it for over 50 miles over the past 2 weeks with no problem. now all of a sudden, It will run for a minute or two and only if i run the choke. Open up the carb drains and nothing.

Answer
Hi Bill,

The fuel valve on your gas tank
is operated by engine vacuum.

There is a small rubber diaphragm
on it that may have pin holes or
maybe the vacuum hose is plugged
or fell off the fuel valve.

There is also a filter screen inside the
tank on the fuel valve as well
as a small screen inside
the fuel valve bowl.

Unscrew the bowl and pull the screen
down and out and see if it is
plugged. There may be an o-ring
holding the screen in.
Try not to damage anything as
it can be hard to get parts.

The fuel valve could be removed after
draining the gas so you can inspect the
vacuum diaphragm if necessary.

Check online for parts first as there may be
a rebuild kit if you are lucky.

Check the vacuum hose is clear and connected
to the engine intake also.


Good luck,
Wayne S.
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