Fuel Petcock vacuum

[domains]

Hi guys...

Just bought 1982 400 .... Is the Fuel Petcock vacuum needed? First time I ever saw one... does it work as a fuel pump?

Bikes bine sitting since 1984 need to clean tank and carbs and noticed this.

 

[xschris]

If you want to gas form it other than when it is set on prime you will need it. The vacuum pulls a diaphragm with a o-ring on the end to let the fuel flow.

 

[domains]

Yes I know it should work as a pump but why place one on a gravity feed gas tank?

noticed on reserve it bypasses

 

[WT100]

Is that true that it will work without vacuumed in reserve mode?

 

[domains]

i took off Petcock and in reserve its free air flow.

 

[domains]

I'm a mechanic but never saw this system... why place a fuel valve on a gravity feed motor.. only fathom i can grasp is to block float valves leak to bypass fill base with gas and ware rod bearings for noobs.

 

[HoughMade]

The vacuum petcock is not a pump of any type. All the vacuum does is pull a valve open so the gas can flow by gravity. The advantage over a manual petcock is that you have to remember to turn it on. The disadvantage is that they frequently leak and need to be rebuilt.

 

[HoughMade]

I'm a mechanic but never saw this system... why place a fuel valve on a gravity feed motor.. only fathom i can grasp is to block float valves leak to bypass fill base with gas and ware rod bearings for noobs.

That's exactly what it is for.

 

[domains]

If carb floats valves stick your not fucked

unless you reserve