GAS SHUT OFF

My shut off valve is leaking and I have taken it off and pland to rebuild it.

Here is my question mine has RES. for reserve stright up. 1/4 thru to the right gives me PRIME we know what it is for. 1/4 turn further to the right says ON we know what it is for. What I want to know is where is off.

 

There is no off, RES and On should only allow gas to come out when the engine is running. That is why there is a vacuum line coming from the #2 intake. The vacuum pulls on a diaphragm in the petcock to open the flow.

 

OFF is at the Hardware Store.

Get a Briggs & Stratton Fuel Shut-off Valve and put it to the right of the Petcock.

Then, ... you got an Off!

 

Yes, I have the small engine shut off valve on mine and it works just fine. It's just easier than rebuilding the vacuum petcock.

 

Easier, cheaper, and gives you peace of mind knowing that it WILL stop the fuel flow.

 

i need to check the spacing on the new petcock i bought . i bought a manual petcock for my virago herd about it right from the virago forum. i believe its the same spacing right from yamaha cost 20 bucks. i figured by the time i added 2 aftermarket petcocks 1 in the fuel line 1 in the vac line to the petcock (alout of times when they fail they fill the cyl thru the vac line . I have a maxim x .but will check the part numbers for the seca and earlier maxims .Also will post a link for the information here is the yamaha part number to use from what i see xj 650 is the same $19.98 from yamaha will take a pic in a few min and post it 21V-24500-10-00 just make sure bolt spacing is 34 mm the screen comes off and you can cut the extension pipe to proper height if you want to get exactly the same as factory on regular posisition

 

Thanks guys.After reading your posts I find my shutoff valve is more messed up than I thought. When I removed the tank there was no second line going to my shut off valve. I have been using it in the prime position. The reson for the rebuild is it only leaks in the on position. Going down the road I smeled gas sure enough petcock leaking. Where exactly does the second line go comming from the petcock. If I understand the manual it says to the bowl of the far left carb. But going to the bowl will not give vaccum needed will it??

 

There should be two Ports to hook-up Hoses too on a OEM Petcock.

The FUEL Outlet --- (Large)
The VACUUM Port -- (Small)

The Fuel Ports sends Gas to the Carbs.
The Vacuum Port needs a Line coming from an Intake Manifold Vacuum Nipple.

The Vacuum Line is normally run to #3 Manifold.
But, as long as it goes to any Manifold ... its OK.

Nothing goes directly to a Fuel Bowl.
The Gas Line to the fill the Fuel Bowls runs to a "T" above the Bowls where the Fuel Gallery is..

 

this is a manual petcock to replace vac operated on of reserve

 

Man I see the need for an inline filter with a shutoff valve...
2 birds......

 

When I installed my shut off valve, I used 1" fuel line to connect the valve to, then another even shorter piece of fuel line to the 90 degree fuel filter going down to the carbs and it fits perfect ('82 750 Seca) No need to ever touch the petcock anymore.

 

My petcock has not worked right since I bought the bike. The vacum part has not even been hooked up. So now that I have it off I am going to fix it and make it work the way it should.

I have put 18000 miles on my XJ 750 in 2 years and you do have to work on it once in a while but it is worth it.