Do I need a petcock?

[The Tin Man]

So get your minds out of the gutter. Now.
I'm running an RD 350 Tank on my xs. The petcock doesn't work it interferes with the motor. I've made a block off plate and there are two other fuel outlets is there any reason apart from when I remove the tank why I need inline taps? I'm running a filter or each and one line to each carbie. It's getting busy if I put inline taps so Im thinking if the carbs don't leak ( new Mikunis) then I can get away without taps.
So who turns the fuel off whenever that are not riding?

 

[650Skull]

Relying on the float and float valve, to stop the fuel is not a fuel stop measure...........

 

[The Tin Man]

Relying on the float and float valve, to stop the fuel is not a fuel stop measure...........

so you always turn the petcock off?

 

[mikesim]

My '79 Special has vacuum petcocks thus I really have no means of physically turning them off. I must rely (hope?, cross-fingers?) that the vacuum system works as intended. Having said that, I think it would be prudent to have some means of assuring that the fuel was turned off, especially during storage. Floats have been known to stick and crankcases have been know to fill with fuel...... I'm just sayin'.....

Mike

 

[Downeaster]

Always. That's why vacuum petcocks were used on later models.

As to leaky carbs, it's not a matter of IF a float will stick, but WHEN.

 

[Paul Sutton]

Back in the 70s - 80s all my fiends said "Always turn your petcock off when you park". It was just accepted by all that the float would stick at some point. Now to the question - I do not know if anyone has tried replacing the XS650 petcock with a direct feed line and a fuel pump (acts as a shut off valve). Perhaps the float valve is no rated for a fuel pump????

 

[gene xs]

You need a shutoff of some kind. These fuel systems are 40 years old at this point. Even with filters, it's not uncommon for a float to stick a bit or to get a small piece of contamination in the float valve (it happens once in a while on my RD350). When that happens, you get fuel in the crankcase and may hydraulically lock the engine - not good at all.

I turn off the petcocks on all my bikes between rides. It's cheap insurance.

 

[gene xs]

Lowes sells in-line lawnmower fuel valves for $10 that should fit and work.

 

[Mailman]

it's not a matter of IF a float will stick, but WHEN.

What he said.

 

[jay760]

Use an in line fuel tap, I use 1/4" full bore tap on mine

 

[cra-z1]

I would just run the lines to the carbs. Then you can come back and tell us what happens when the crank fills with gas. Considerer it a scientific experiment.

 

[Paul Sutton]

Just a thought . The following style petcock could be attached to one of the screws on the carburetor diaphragm cover:

See Ebay UK: https://www.ebay.co.uk/itm/UK-6mm-I...304709&hash=item5489fa39a4:g:cMIAAOSwoCNfTccX

 

[fredintoon]

File the turn-limiting nubbin off the stop-plate and cut the gas tap handle short enough to point straight up to give the stock petcock a true OFF position at no cost
OR
Swap in a MikesXS true off petcock for a C-note+ if you include the shipping.