Fuel Problem

[David]

I took my '82 Vision to the shop to have the carbs rebuilt.
When I went to pick up the bike, gas was pouring out
of the carb over-flows. It even was flowing through the carbs
and cylinder and filling the exhaust pipes.
They told me it was because the fuel petcock was bad.
It was working fine when removed from the bike over
a year ago.
Could this really be the problem, or is it a
bad carb rebuild???

I looked at the shop manual diagram of the petcock,
it seems simple, what could cause this problem,
and how can I fix it??

[George R. Young]

Even if the petcock is stuck open, the float valves in the carbs are supposed to cut off fuel flow once the fuel reaches a certain level.

Sounds like the people who 'rebuilt' your carbs may not have checked the float valve operation.

[Cdnlouie]

George is right on the petcock issue, the floats should really stop that flow if working correctly.

Did they charge you for new needle seat o-rings? They really need to be replaced or fuel just leaks straight into the bowls even with proper float height.

The volume you are describing means that your petcock is definitely not stopping fuel flow and your floats are set too high or o-rings are leaking (or all of the above). ?You really need to get these addressed one by one (Make sure the petcock is not on prime which does not shut the fuel off).

[Chris Monell]

 If i remember right (owned a Vision years ago), the petcock has a vacuum hose going to it to shut off the fuel when you shut off the engine, if the diapram in there is bad I think fuel can run into the intake manifold and then take the path you described. Easy to check though pull the vacuum hose from the petcock and if fuel runs out that's the problem. That petcock may have only been on the later ones, wish I could find my old factory shop manual, if I do we'll start the bidding.

[Rick G]

All of them have a vacuume petcock, most of the time  you can dip them in  carb cleaner over night(take them apart first!  and change the oring on the post in the center of the diaphram.