Vacuum Operated Petcock

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bikebone

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Aug 26, 2012
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Location
Waxahachie, TX
I can't seem to remember to turn off the petcock on my 1100 and all I've been doing for a month is getting the thing ready to ride. My other bikes all have vacuum operated petcocks and you never have to think about turning them off, so I started looking for some way to add an in-line petcock that was vacuum controlled. Pingle offers one, but it is $125. Ouch!!! After looking at a zillion different applications, I came across a petcock off of a KFX700 or KSV700 Kawasaki. I found one on EBay for $7.95 with free shipping; my kind of deal! I made a simple bracket and mounted it near the fuel pump. Works like a champ.
Now I'm installing a switch that won't let the bike start when the side stand is down. I know it's second nature for you guys to turn the gas off or put your kick stand up, but I haven't owned a bike in years that didn't those two features.
 
With no pics, it dint happen..... :smilie_happy: :smilie_happy: :smilie_happy:
Both good ideas, tho. :good:
Mama & I will be down in Waxahachie tomorrow...going diggin thru the antique shops, and havin some fine grub at da Catfish Plantation....yummy!
 
Here's a picture of that petcock. It's tested and works great, but I still have a little work to do, like matching up all the clamps, etc.
goldwingpetcock008.jpg

By bikebone at 2012-09-01
 
that's what I call a Mod..man, :clapping: yes....so this mod will stop the flow of fuel once the engine is shut down? So is that what we are doing here? :shock: :clapping:
 
Yep! When you shut off the engine, this petcock stops the flow of fuel just like any modern bike. I failed to mention that I am drawing the vacuum off of the #3 vacuum port that you use when balancing the carburetors. You can see the hose in the photo.
 
I get the point,however I have never had to much success relying on vacuum petcocks.Had one on a GS850 that was a constant PITA.As well as a couple KAWs that were not to reliable.Of course having an OFF position (which I assume you still have) would make it nicer.

I to am curious if there is a PRIME position for starting after a short lay up?
 
I think your problems with the vacuum operated petcocks were isolated. To my knowledge, all of the currently made motorcycles have vacuum petcocks. I have owned a bunch of bikes over the last 40+ years and all of them made after about '85 had this kind of petcock; none of them ever gave me a problem. The engine creates vacuum anytime it is turning over; whether on the starter or when it's running, consequently the fuel will flow. This petcock does have a prime position. If by some chance it would become a problem, just put it on "prime" and you are back to relying on the original petcock. Easy enough!
 
bikebone":2999vrn2 said:
I found mine on EBay for only $7.95 freight paid.
Click to expand...
when you went on ebay, what did you key in to find it? And what did you use for the hose connection at the intake..?
 
When you look on EBay, search for a petcock for a KFX700 or KSV700 Kawasaki. I replaced the screws (for balanceing the carburetors) on the intake manifolds with Motion Pro 5mm brass adapters. These come with rubber caps that seal the vacuum when not balancing the carbs. I simply uncapped the one on the #3 intake & ran a hose from there to the petcock.
 
bikebone":43omz8pe said:
I think your problems with the vacuum operated petcocks were isolated. To my knowledge, all of the currently made motorcycles have vacuum petcocks. I have owned a bunch of bikes over the last 40+ years and all of them made after about '85 had this kind of petcock; none of them ever gave me a problem. The engine creates vacuum anytime it is turning over; whether on the starter or when it's running, consequently the fuel will flow. This petcock does have a prime position. If by some chance it would become a problem, just put it on "prime" and you are back to relying on the original petcock. Easy enough!
Click to expand...

Not to isolated to just me.
The forums,whether it be the GS,KZ or CB forums, are full of people beefin about them,and looking for a way to get back to a manuel petcock.Most of the time ,on the GSs anyway,they dont shut off imediatly.

Anyway,with the stock valvle to override it to OFF you should be OK,But then why have it then.

No offense.I am an obsesive compulsive traditionalist who does "routines" like bad habits and likes manuel/mechanical "I DID IT" gradification. :rtfm:
 
My 2005 KLR-650 has a vacuum petcock and it started shutting me off on a 50 mile trip one day last summer. I has to stop and work on it on the side of the road twice before I figured out what it was. I then figured out how to temporarily bypass it and went to the Kawasaki dealer in the next town and asked for a new one. They said oh we don't stock them but can have it in about a week. I declined to order one fifty miles from home and ordered a kit online for about half the price of the assembly. I have since ordered a kit to disable the vacuum portion just for my owns piece of mind.

I won't one to the wing any time soon... :mrgreen:
 
You certainly don't need one of these if you have the good habit of turning off the standard one. Unfortunately, I don't have that good habit (I do have a lot of bad ones). I, too, was into GS Suzuki's at one time and had a lot of fun with them. I'd gather up two or three really scuzzy ones and build one good one and ride it all over the country. Never had a problem with a petcock. There's a lot to be said for dumb luck.
 
Tory":28u1kepm said:
Not to isolated to just me.
The forums,whether it be the GS,KZ or CB forums, are full of people beefin about them,and looking for a way to get back to a manuel petcock.Most of the time ,on the GSs anyway,they dont shut off imediatly.
Click to expand...

Same with my XS750. Their vac-petcocks fail and let the gas go into the engines. Un-noticed the gas-oil wears out internals and destroys the engine. I mod'ed mine to become manual petcock.

Hopefully today's vac-petcocks are reliable.
 
Bypassed the vaccum petcock on my 91. At high end you don't have enough vaccum to keep it open, when you get some mileage on it. Any other time it was fine Denver
 

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