Standard Petcocks

[Gallaecus]

what is the advantage of not using the vacuum assist to pet cock?

makes it manual?

only works in prime?

do I run two vacuum lines from carb boots ? 1 and 4 or 2 and 3 ?

i heard i can file the nub off the backing plate and be able to turn shut off in the up position creating an off position.

what is the best way to go about this. i would like to have on and a reserve.
would i be correct in saying if i dont use vacuum, then prime is on and ...on and reserve is off?

[TomB]

what is the advantage of not using the vacuum assist to pet cock?

makes it manual?

only works in prime?

do I run two vacuum lines from carb boots ? 1 and 4 or 2 and 3 ?

i heard i can file the nub off the backing plate and be able to turn shut off in the up position creating an off position.

what is the best way to go about this. i would like to have on and a reserve.
would i be correct in saying if i dont use vacuum, then prime is on and ...on and reserve is off?

I filed off the nub, it does allow you to manually turn off the petcock in case the vac side of the cock isn't working, which happened to me once when trying to remove the tank I had gas pouring everywhere. Ironically I was removing the tank to repair the cock

I guess removing the shut off spring might work, that way the shut off won't work enabling "on" and "reserve" and with the nub filed you have an "off". You wouldn't need the vac pipe from the inlet then.

[crazy steve]

There is no advantage to not using the vacuum with standard petcocks...

Yes, without vacuum you'll only get fuel in the 'prime' position. This position also draws fuel at the same point as 'reserve', so when you're out of fuel, you're out....

I've looked at what it would take to 'convert' these to full manual, but given the mods needed to the petcock body and fabbed parts, it's far easier to just rebuild them to OEM.

You can hook the vacuum lines to any two carb boots, but most use 2/3 to semi-conceal the lines.

[motoman]

There is no advantage to not using the vacuum with standard petcocks...

Yes, without vacuum you'll only get fuel in the 'prime' position. This position also draws fuel at the same point as 'reserve', so when you're out of fuel, you're out....

I've looked at what it would take to 'convert' these to full manual, but given the mods needed to the petcock body and fabbed parts, it's far easier to just rebuild them to OEM.

You can hook the vacuum lines to any two carb boots, but most use 2/3 to semi-conceal the lines.

+1...........modifying the Standard petcock for an 'off' position, IMO, is a bad choice.......fix the damn needle/seat problem. In the past, I've 'fixed' two sets of Standard petcocks that I noticed were weeping fuel with tank off. No 'kits' necessary for either. Just dis-assemble, clean everthing good, carefully pulled each spring ever so little as to create a bit more tension(not too much, as to overcome vacuum pull for opening), fine emory paper polishing rotating piece contact surface, and put back together using a film of dielectic grease on gaskets for any 'squish' movement. That's been 9+yrs. now and not so much as a weep from petcocks or gasket contact areas.

[natemoen]

+1...........modifying the Standard petcock for an 'off' position, IMO, is a bad choice.......fix the damn needle/seat problem. In the past, I've 'fixed' two sets of Standard petcocks that I noticed were weeping fuel with tank off. No 'kits' necessary for either. Just dis-assemble, clean everthing good, carefully pulled each spring ever so little as to create a bit more tension(not too much, as to overcome vacuum pull for opening), fine emory paper polishing rotating piece contact surface, and put back together using a film of dielectic grease on gaskets for any 'squish' movement. That's been 9+yrs. now and not so much as a weep from petcocks or gasket contact areas.

So what is wrong with taking that little tab off the top so that you can rotate the handle to the up position for an off?

Mine work fine but I still turn the off (up). Whenever I get off the bike.

[fredintoon]

- - - I've looked at what it would take to 'convert' these to full manual, but given the mods needed to the petcock body and fabbed parts, it's far easier to just rebuild them to OEM. - - -

Hi Steve,
all it takes is to swap each lever over to the other tap body.
ON becomes OFF; RES becomes ON and PRI becomes RES.