Possible gas leak from carbs or petcock issue

agentbad · August 24th, 2013, 03:55 PM

So I have noticed there is some gas on the bottom of my carbs and I can smell it sometimes when I am riding for a while. It's not gushing out or anything but when I run my hand on the bottom of the carb I can feel the gas and see it if I am looking right at it. I took a closer look today and took n4mwd's advice to pull the hose off the petcock when it's on the ON position sure enough it still leaks fuel. I've aslo notice a bit of gargle sound from the carbs when I start up especially when it's cold so maybe I have a messed up float too I am not sure. Where should I go from here? The bike only has 6400 miles on it but the previous owner didn't take care of the bike. It runs and idles well other then the gas issue.

Motofool · August 24th, 2013, 06:14 PM

Quote:

Originally Posted by agentbad

.........Where should I go from here?........

You could go reading Chadd's thread:
http://www.ninjette.org/forums/showthread.php?t=146834

agentbad · August 26th, 2013, 05:16 AM

I'm not having any leakage from the overflow tube just on the carbs themselves. If the petcock is turned to the On position should gas still come out because it doesn't leak when it's off? I'm thinking about just buying another set of used carbs.

Motofool · August 26th, 2013, 07:15 AM

Quote:

Originally Posted by agentbad

I'm not having any leakage from the overflow tube just on the carbs themselves. If the petcock is turned to the On position should gas still come out because it doesn't leak when it's off? I'm thinking about just buying another set of used carbs.

Carbs overflow when one or both float valves don't close properly.
They can leak through the bowls' gasket or the tube, the source is the same.
Petcocks that work properly are activated by the vacuum of the engine: engine off-no flow for any position.

You can service and repair your carbs, used carbs are not necessarily better than yours.
Here you can learn how to do it yourself:
http://faq.ninja250.org/wiki/Intake

CWLESQ · August 26th, 2013, 07:54 AM

I had a very similar problem. Assuming the float bowl drain screw is snug, the gas your finding on the bottom of the carb is evidence of a float/float needle issue. I would inspect the float needle valve within the carb and set your floats to spec (17mm), that should solve your problem.

agentbad · August 26th, 2013, 10:36 AM

Quote:

Originally Posted by CWLESQ

I had a very similar problem. Assuming the float bowl drain screw is snug, the gas your finding on the bottom of the carb is evidence of a float/float needle issue. I would inspect the float needle valve within the carb and set your floats to spec (17mm), that should solve your problem.

Okay I'll give that a try this week.

agentbad · December 13th, 2013, 07:22 AM

Well it's the petcock that seems to be the source of the leak. I took the fuel hose off and it still dripped when it was on the ON position. If I put it on reserve it was a lot worse. If I shut off the petcock and leave the bike for while the carbs are clean when I come back. If I don't do this they collect gas on the bottom and around the idle adjustment knob. I also noticed a small gas puddle where I park the bike for a while. Another issue is when I took the vacuum hose off the metal nipple on the petcock came off with it. I tapped the thing back into place with the back of screwdriver and it seems to still be working alright but because of this I am considering just getting a brand new oem petcock instead doing a rebuild. Any thoughts?

jkv45 · December 13th, 2013, 07:45 AM

Quote:

Originally Posted by agentbad

Well it's the petcock that seems to be the source of the leak. I took the fuel hose off and it still dripped when it was on the ON position. If I put it on reserve it was a lot worse. If I shut off the petcock and leave the bike for while the carbs are clean when I come back. If I don't do this they collect gas on the bottom and around the idle adjustment knob. I also noticed a small gas puddle where I park the bike for a while. Another issue is when I took the vacuum hose off the metal nipple on the petcock came off with it. I tapped the thing back into place with the back of screwdriver and it seems to still be working alright but because of this I am considering just getting a brand new oem petcock instead doing a rebuild. Any thoughts?

Definitely fix the petcock, but it's not the real problem.

A vacuum petcock is just a back-up system. It's the job of the needle/seat/float to stop the flow of the gas in the carb - not the petcock.

If the needle and seat are closed securely you don't need a petcock that stops fuel flow unless there is vacuum (engine running).

August 24th, 2013, 03:55 PM	#1
agentbad ninjette.org sage Name: bob Location: Earf Join Date: Apr 2013 Motorcycle(s): 2005 Ninja 250, 2006 SV650N Posts: 642	Possible gas leak from carbs or petcock issue So I have noticed there is some gas on the bottom of my carbs and I can smell it sometimes when I am riding for a while. It's not gushing out or anything but when I run my hand on the bottom of the carb I can feel the gas and see it if I am looking right at it. I took a closer look today and took n4mwd's advice to pull the hose off the petcock when it's on the ON position sure enough it still leaks fuel. I've aslo notice a bit of gargle sound from the carbs when I start up especially when it's cold so maybe I have a messed up float too I am not sure. Where should I go from here? The bike only has 6400 miles on it but the previous owner didn't take care of the bike. It runs and idles well other then the gas issue.

August 26th, 2013, 07:54 AM	#5
CWLESQ ninjette.org newbie Name: Chadd Location: Cherry Hill Join Date: Aug 2013 Motorcycle(s): '07 Ninja 250 Posts: 5	I had a very similar problem. Assuming the float bowl drain screw is snug, the gas your finding on the bottom of the carb is evidence of a float/float needle issue. I would inspect the float needle valve within the carb and set your floats to spec (17mm), that should solve your problem.
	1 out of 1 members found this post helpful.

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August 26th, 2013, 05:16 AM	#3
agentbad ninjette.org sage Name: bob Location: Earf Join Date: Apr 2013 Motorcycle(s): 2005 Ninja 250, 2006 SV650N Posts: 642	I'm not having any leakage from the overflow tube just on the carbs themselves. If the petcock is turned to the On position should gas still come out because it doesn't leak when it's off? I'm thinking about just buying another set of used carbs.

December 13th, 2013, 07:22 AM	#7
agentbad ninjette.org sage Name: bob Location: Earf Join Date: Apr 2013 Motorcycle(s): 2005 Ninja 250, 2006 SV650N Posts: 642	Well it's the petcock that seems to be the source of the leak. I took the fuel hose off and it still dripped when it was on the ON position. If I put it on reserve it was a lot worse. If I shut off the petcock and leave the bike for while the carbs are clean when I come back. If I don't do this they collect gas on the bottom and around the idle adjustment knob. I also noticed a small gas puddle where I park the bike for a while. Another issue is when I took the vacuum hose off the metal nipple on the petcock came off with it. I tapped the thing back into place with the back of screwdriver and it seems to still be working alright but because of this I am considering just getting a brand new oem petcock instead doing a rebuild. Any thoughts?