Author Topic: Gas Tank Vacuum Lock?  (Read 482 times)

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Offline Ride&time

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Gas Tank Vacuum Lock?
« on: April 22, 2013, 01:38:24 AM »
I recently could not get my bike to run more than 5 miles without trying to die. (usually less distance) I did manage to ride about 50 miles to a local ride with other concours owners Sunday. Got dropped a couple times they had patience and waited. Talked with them in regards to my problem and one COG member said he had the exact same trouble and it was his gas cap. I had difficulty believing this could be something that simple. It was a great ride great group to ride with but when I was in a good place to leave the ride I said goodbye's and headed for home. raining allot of the way home but when it stopped I opened my gas cap and rode and the problem with the bike cutting out or bogging down or dieing went away. I will go out soon and put it through more tests but I really think its some kind of gas tank vacuum. IS THIS POSSIBLE? A Few days ago I removed the California emission's stuff and there were 4 hoses coming off the tank. Two of these loop through the emissions stuff, one is a vent for the gauge and one is a vent for the tank? I can hook all that stuff back up but if this is the problem it would be nice to not have to use the Cali stuff. Anyone experience a gas tank Vacuum lock? This is what I decided to call it not knowing what is called if it is possible.

Thanks in advance for your reply - replies.
Mark

Offline C. Moore

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Re: Gas Tank Vacuum Lock?
« Reply #1 on: April 22, 2013, 03:46:21 AM »
It sounds like you have found the problem. The gas cap is designed to vent. If that vents gets clogged the bike will cut out. I took my cap off, took it apart and cleaned it when I had this problem. It has been good since I did that. You could also have crude in the tank. I would start with the gas cap since the bike will run with the gas cap open. Good luck.
'10 C14  Dallas, Texas
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Offline SCATES

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Re: Gas Tank Vacuum Lock?
« Reply #2 on: April 27, 2013, 11:46:19 AM »
+1 on gas cap vent problem.

The gas cap has small o-rings "2 orange rubber vents" that harden and/or break, resulting in vent malfunctions.

In my case, the cap refused to vent and when the tank was mostly full of air, in hot weather, the fuel tank would become over-pressurized, resulting in fuel flowing into the airbox.  Manual venting of the gas cap (when it was low on fuel, in hot weather) helped me finish the other 1500 miles of my trip.

I just checked the fiche and no Kawasaki parts appear inside the gas cap section.  Finding fuel-resistant o-rings in the correct size might work but I haven't experimented with them yet.
« Last Edit: April 27, 2013, 09:03:03 PM by SCATES »

Offline Capo

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Re: Gas Tank Vacuum Lock?
« Reply #3 on: April 27, 2013, 12:42:30 PM »
There are 2 orange rubber vents, they are burried deep in your caps guts. Take one of them out. There is instructions with pics on here I believe. Also use the least amt. of fuel line possible and simple downhill routing.
James in Tampa. Currently being enjoyed are...04 C10,  86 C10 "Cooper" , 04 Honda vt750 "Christine" . The  only previously owned needing mention would be 74 gt750, I cant believe how many of us had a "water buffalo" !!!

Offline Mortech

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Re: Gas Tank Vacuum Lock?
« Reply #4 on: April 27, 2013, 08:52:00 PM »
Well removing that bottom valve in the cap will fix that problem, its what cured mine from doing the same . Now I feel bad for not following back up I-5  ::)
« Last Edit: April 27, 2013, 09:04:46 PM by Mortech »
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Offline Ride&time

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Re: Gas Tank Vacuum Lock?
« Reply #5 on: May 01, 2013, 04:42:42 PM »
All is good with that cap issue now. Thanks for the help guys. Yeah Mortech don't feel bad about not following. Problem  did not get worse and we had made it through a fair amount of miles that day. You had told me about having had a problem with the cap so about half way home I opened the cap and it ran great. That got me on the right track and I found I capped the wrong line out when removing the California emissions. (had to open it stuck a hose on it and a small gas filter just so it would stop any larger dust particles. (working as a tank air filter)