Vacuum Petcock Bypass

Correctly servicing the Carburettors on these bikes is paramount to good running and fuel economy so any work done will pay back in better mileage :)
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Vacuum Petcock Bypass

Postby Gman » Sat Jun 13, 2009 10:43 pm

If you are having trouble with the Vacuum Petcock on this Type of Carburettor it is easily bypassed,

1:Cap the vacuum port on the intake manifold on the right side.

2:Take apart the petcock valve and remove the spring that is against the diaphragm.

3:Put it back together and connect the two vacuum line ports on the petcock to each other.

The Vacuum Petcock only stops fuel flow to the Carbs when the engine is stopped.It's not used on the European models and was probably part of the stricter import rules for the American versions.If your Carb Float system
is correct it's not needed IMHO,

Thanks to Ookie Wonderslug on CC's site for this little gem.

From VooDoo Surfer.

Another way to fix the petcock issue is to take the spring out and cut the center of the diaphragms out with an exacto and leave the outside as a gasket. that way you remove any obstructions all together.

Also see this thread for pictures,
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Re: Vacuum Petcock Bypass

Postby slateroc24 » Mon Jun 22, 2009 11:01 pm

I even went as far as to cut out the center of the diaphrams leaving enough to work as a gasket but to make sure there was no way it could restrict any fuel flow.
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