Tired of vacuum problems with your stock petcock? Don't want to buy a new one for $100 (or less for a Pingel)? Here's how to turn your stock petcock into a gravity fed petcock with no extra parts. And all you need is a few basic tools.
Pic 1 - An exploded view of all the parts of the petcock I need to take apart (yeah, the screen is still in the tank, not to worry).
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In this picture, you can see how all the pieces fit together. On the left side of the spring is the black disc you see in the pic above. It snaps onto the diaphragm.
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The way it works is the vacuum from the left side of the image pulls the diaphragm against the spring allowing the fuel to flow. When no vacuum is present, the diaphragm is pushed closed by the spring. So how do you fix this?
Like so:
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The spring fits perfectly on the other side of the diaphragm into the petcock and against the spring. Now the spring is forcing the diaphragm open instead of closed.
I reassembled it all...
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Put the petcock back on the bike and tested it. In the off position, no fuel. Turn it to on or reserve, and fuel flows out!! It WORKS!
I now have a gravity fed petcock for nothing more than my time.
Note - Added info for safety information.
The safety implications involve the fuel continuing to flow even if the bike goes down and the engine dies. Honda is required by law to have this vacuum petcock in place to prevent a fire hazard.
The other concern that I have is this, if you don't religiously turn OFF the petcock, you will have a bunch of gasoline in your crankcase. This will occur because the 'weight' of the gasoline sitting above the float needle will cause fuel to by pass the needle and run down the intake manifold into the cylinders.
If enough gasoline gets into the cylinder and pools on top of the piston, upon starting there could be a catastrophic failure of the connecting rod and or piston because according to Pascals' Law, liquids are not compressible but instead exert equal pressure in all directions.
Pic 1 - An exploded view of all the parts of the petcock I need to take apart (yeah, the screen is still in the tank, not to worry).
In this picture, you can see how all the pieces fit together. On the left side of the spring is the black disc you see in the pic above. It snaps onto the diaphragm.
The way it works is the vacuum from the left side of the image pulls the diaphragm against the spring allowing the fuel to flow. When no vacuum is present, the diaphragm is pushed closed by the spring. So how do you fix this?
Like so:
The spring fits perfectly on the other side of the diaphragm into the petcock and against the spring. Now the spring is forcing the diaphragm open instead of closed.
I reassembled it all...
Put the petcock back on the bike and tested it. In the off position, no fuel. Turn it to on or reserve, and fuel flows out!! It WORKS!
I now have a gravity fed petcock for nothing more than my time.
Note - Added info for safety information.
The safety implications involve the fuel continuing to flow even if the bike goes down and the engine dies. Honda is required by law to have this vacuum petcock in place to prevent a fire hazard.
The other concern that I have is this, if you don't religiously turn OFF the petcock, you will have a bunch of gasoline in your crankcase. This will occur because the 'weight' of the gasoline sitting above the float needle will cause fuel to by pass the needle and run down the intake manifold into the cylinders.
If enough gasoline gets into the cylinder and pools on top of the piston, upon starting there could be a catastrophic failure of the connecting rod and or piston because according to Pascals' Law, liquids are not compressible but instead exert equal pressure in all directions.
. It's like a different bike. I tuned the a/f screw out 2.5 turns.
