Fuel petcocks help !

[DreadRock]

I picked up apair of xs650 petcocks from a DTT member .

Im putting them on this tank...

on a stock 75 xs500 , im putting new carbs on it thinking 28 or 30mm carbs. can i use these petcocks ? they seem two times as big as the ones i pulled out of my stock tank. and they have two nipples i know one is gas is the other ....?

 

[Redbird]

Assuming they fit the tank... The size shouldn't matter as the needle valves will only allow in so much anyway. As for the two nipples, they're usually one for each carb. You can block one off if you don't need both.

 

[DreadRock]

Yes they fit the tank NP there everything lines up right. they just seem .... well big on the side of the tank lol but will do till i find something maybe lil cooler. guess ill have to wait till i get my carbs to see what i need and dont need . thanks guys

 

[Big R]

If I had to guess, I would say that other nipple is for a vacuum line (Suzuki uses them all the time. I can't read what it says on the petcock, but are tell 3 settings "on, reserve, and prime"? If so, than you have to run it on prime and block off the other nipple.

 

[DreadRock]

Yea looks like they do have prime on them. they will work but still dont like how big they are might look for diff pair lol will see

 

[Big R]

One other thing: on a Suzuki vacuum-type petcock, the "prime" position flows gas from the reserve tube. So while you can use the petcock for a non-vacuum setup, you are basically running on reserve all the time.

Maybe those are different, but I did want to point that out.

 

[Redbird]

Ah, hadn't thought of the "prime" or vacuum scenarios.

The petcock on my Yamaha has two ports, one for each carb.
There is a way to eliminate the vacuum pump from the petcock, but I'm hammered (shitty news on the homefront) and can't focus on it right now, and don't want to give you crappy information.
Rich knows his shit though... listen to him

 

[Big R]

Hope everything works for ya Red- you've got an ear waiting if ya need it man.

It is possible to disengage the Suzuki vacuum pretty easily by taking the petcock apart. But then the problem comes from the 3 available positions - since there is no "off" position.

 

[Redbird]

Thanks Rich, I appreciate it. It's kinda "classified info" right now, but y'all will know before anything happens

And Rich is right, with no "Off" position, you really have to trust in your float needles.

 

[crazypj]

One other thing: on a Suzuki vacuum-type petcock, the "prime" position flows gas from the reserve tube. So while you can use the petcock for a non-vacuum setup, you are basically running on reserve all the time.

Maybe those are different, but I did want to point that out.

That's for vacuum line from manifold.
I don't have any issues with them, not sure why so many people do have problems?

 

[Big R]

I've been reading a lot about the vacuum petcocks on the GSResources - seems the majority of folks say replace it with an OEM unit. They say the original lasted for 30+ years, so another one should last as long too.

I've had only 1 fail in me and it was just an inconvenience. I went out to the garage to ride the bike to work to find the majority of what was in my gas tank had bypassed the petcock and found its way into my crank case. Oddly enough, the floats seemed to be over powered by a full tank of gas - there was about 1 gallon left in the tank.

 

[DreadRock]

thanks for the info guys ! the good news is rideing season is up here for the winter so have 6 months to work on it lol bad news is riding season is up for 6 months lol and as i can be a lil slow somethimes im thinking might clean these ones up and look for a better fitting pair or ill have gas everywhere ! Red hope everything works out for you man ! again thanks guys