Leaks & Idle - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Carbs and Fuel System
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post #1 of 14 (permalink) Old 08-12-2011, 04:01 AM Thread Starter
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Leaks & Idle

ok so i went to start my bike up the other day and noticed that it stinks like gas, and that there was a puddle on the ground. i tried to start my bike and it would not start due to the excessive amount of fuel in the cylinders. so i had to take out the plugs and hit the start button to get all the excess fuel out. it started right up after and had no issues. the problem im having is that sometimes the gas leaks out, i tried all positions of the petcock and it does the same thing, also the bike will stay at a constant 3-4k rpm for no reason. rev it up and down to 3-4k it stays. u can also hear a whistling sound from the gas cap like it is air escaping from the tank. any ideas how to resolve these issues?


leaky gas & gas cap whistle & weird rpm's


thanks!
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post #2 of 14 (permalink) Old 08-12-2011, 08:41 AM
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fuel in the cylinders ? suspect the float in the carb(s) sticking. try seafoam

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post #3 of 14 (permalink) Old 08-12-2011, 10:53 AM
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I had an old Suzuki that would do the same thing. Turns out the vacuum diaphram in the petcock had a small hole. No matter where the petcock was positioned, it would drip down the vacuum line into the # 2 cylinder (and sometimes run back into the balancer tubes and fill #1 as well). When running, at least one of the cylinders was getting extra gas, essentially running on choke, causing my idle speed to be high.

I'd recommend pulling the lines off of your petcock and see if any develop a drip at various petcock positons. Remember a rag or something underneath to prevent the fuel from dripping onto your motor, that's never good...
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post #4 of 14 (permalink) Old 08-12-2011, 12:36 PM
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Originally Posted by stuicide09 View Post
ok so i went to start my bike up the other day and noticed that it stinks like gas, and that there was a puddle on the ground. i tried to start my bike and it would not start due to the excessive amount of fuel in the cylinders. so i had to take out the plugs and hit the start button to get all the excess fuel out. it started right up after and had no issues. the problem im having is that sometimes the gas leaks out, i tried all positions of the petcock and it does the same thing, also the bike will stay at a constant 3-4k rpm for no reason. rev it up and down to 3-4k it stays. u can also hear a whistling sound from the gas cap like it is air escaping from the tank. any ideas how to resolve these issues?

leaky gas & gas cap whistle & weird rpm's


thanks!
The whistling from the tank is actually a good sign that the vent is working.
When the vent doesn`t work the bike develops something we call POOGS.
See this link for more info on how to cure and avoid it.
Phantom Out Of Gas Syndrome (POOGS): Correction and Prevention
https://www.vn750.com/forum/showthread.php?t=17572

Gordon

1991 VN 750 -"Cosmic Lady" or "Bad Girl"?
Purchased May 16, 2008
Approx.19,300km (12,000 miles)

H-D windshield
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F&S luggage rack and engine guard
Kury Offset Hiway pegs
July 13, 2016, Riding on the DARKSIDE now, Classic Radial 165/80-15


TOP TEN THINGS A NEW RIDER/OWNER SHOULD DO. Click on link.
https://www.vn750.com/forum/11-vn750-general-discussion/9127-top-ten-items-you-would-suggest-new-owner-do-his-new-ride.html
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post #5 of 14 (permalink) Old 08-12-2011, 01:14 PM
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It could be the petcock diaphram. The fuel is going past the diaphram into the cylinders and when started you are getting to much fuel.
I was thinking that too much vaccuum from the damaged diaphram is causing the whistle sound from the tank.

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post #6 of 14 (permalink) Old 08-12-2011, 07:18 PM
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Check the vent line coming off the petcock, shouldn't be any gas in there. If there is, bad petcock. Or could be stuck float, mine did the same thing and that's what it was.

Start with the petcock, then on to pulling the carbs...

Bike is sold, thanks for the help guys. Ride safe.

Last edited by Freedom; 08-12-2011 at 07:22 PM.
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post #7 of 14 (permalink) Old 08-13-2011, 02:19 AM Thread Starter
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thanks all for the responses, i will be checking it out later today when i get home from work, and ill let u know what it was.
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post #8 of 14 (permalink) Old 08-13-2011, 06:12 PM Thread Starter
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ok so i did as recommended... i took off the petcock to check out an issue with it. there was definately an issue, it had lots of rust particals built up inside it. so i cleaned it out and was checking the parts section on the forum. there is supposed to be a filter that goes ontop the petcock into the gas tank which i am missing so im gunna get another one this friday. i have inline filters i put in anyhow, not knowing there wasnt one in the gas tank. so this friday i will get some seafoam, petcock fuel filter, and will post back how it works out. im also going to take the carbs off and clean them out just incase so i know everything is fresh.....thanks for the help!
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post #9 of 14 (permalink) Old 08-16-2011, 03:43 PM Thread Starter
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ok, no more leaky petcock, got a new petcock gas filter, cleaned tank real nice and added fresh gas and seafoam. only problem is it still has the 4k rpm problem.
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post #10 of 14 (permalink) Old 08-16-2011, 05:16 PM
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Now that you have the petcock problem under control, try turning the idle adjustment knob on the left side of the engine. A little counterclockwise rotation should help bring your idle speed back down to more normal levels. Adjust until set at ~~1,100 rpm.

John

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