Petcock Use? - Kawasaki KLR 650 Forum
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post #1 of 7 Old 01-11-2015, 02:13 PM Thread Starter
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Join Date: May 2013
Location: Panhandle of Texas
Posts: 66
Petcock Use?

I'm older, on the motorcycles I've had in the past, I've always shut off the bike and turned the petcock off. I do the same on the 08 KLR I now have. Is there anything wrong with this practice?
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post #2 of 7 Old 01-11-2015, 02:51 PM
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Location: Tennessee
Posts: 326
Nothing wrong, but probably unnecessary.
I only use petcock valve if I am removing the tank for some reason. Ditto for my last Five or so bikes.

"Chet from Chattanooga"
2009 KLR, blue
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post #3 of 7 Old 01-11-2015, 07:20 PM
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Originally Posted by clogan View Post
Nothing wrong, but probably unnecessary.
I only use petcock valve if I am removing the tank for some reason. Ditto for my last Five or so bikes.
D C,
A good practice to continue, IMO. Keeps the valve handle from sticking and causing a problem later.

No Need to turn it off, the lack of vacuum already turned it OFF.

The fuel valve 'lives' the longest, with-out rebuilding, if we occasionally turn it, for what-ever reason.

Modify at "YOUR OWN RISK"!

Still riding my 1987 KL650-A1. 85,000+ miles & counting
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post #4 of 7 Old 01-11-2015, 11:04 PM
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Location: Benicia, CA
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Yeah, it's a good idea. I never do it though because I invariably forget and have to start my bike twice. I figure the first time it gives me trouble I'll put in an old school petcock, but my 08 has pretty much always been left 'on' and no issues. If you're still in the habit (I used to be), keep doing it. my .02

You might want to switch out for a non vacuum PC if you feel like messing with it, and you're going to leave it "off"

"In a car you're always in a compartment, and because you're used to it you don't realize that through that car window everything you see is just more TV." R. Pirsig

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Soon, we ride.

AKA JD Mader or you can call me "Dan" just not early for dinner.

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post #5 of 7 Old 01-12-2015, 05:00 AM
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Join Date: Jan 2011
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Should you convert to a manually-actuated (no "vacuum") petcock, some "tribal knowledge," some "Internet mythology" to consider:

Some believe trimming the main fuel standpipe increases fuel pressure at the carburetor. Actually, the hydrostatic pressure at the carburetor remains entirely a function of the "head," the height, the vertical elevation of the fuel level above the carburetor; the length of the standpipe has absolutely no influence on fuel pressure.

One definite and actual effect of trimming the main fuel standpipe: Your reserve capacity will be REDUCED, according to the length trimmed.

Yet, go ahead and cut your standpipe as ye wish . . . I have spoken.

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post #6 of 7 Old 01-12-2015, 05:42 PM Thread Starter
1st Gear
Join Date: May 2013
Location: Panhandle of Texas
Posts: 66
I appreciate the information, the FB geniuses made it sound like t was bad for the petcock to be turning it off and on, so I thought I'd ask here for a reliable source.
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post #7 of 7 Old 01-13-2015, 01:12 AM
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Join Date: May 2009
Location: Indiana/ Michigan line at the Lake
Posts: 1,585
Fear of a vac-leak caused me to go with the stock full flow unit.

I've removed all the safety switches and vacuum system to give that
peace of mind of something that can't fail out in the world and stranding me.

The stock petcock can be taken apart. Take out or hole the vac-diaphram
and now it's an old school unit. The back vac nipple as well as the carb need
to be capped off with a no leak snugness.

I have to ride like I did in the 70's and 80's. Turn on the gas, Make sure I'm in neutral,
and have to kick up the sidestand because the bike will keep running. Old school is
fine with this 48yo old fart in training.

Just another option,

This is my son, with whom I am well pleased." ----God
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