Hi,
I woke up this morning to this



I am not sure where the gas is coming from but I did see it dripping off the sides of both carbs. In the picture below you can see one drop of fuel on the bottom of the closest carb and a drop of fuel on the end of the farthest away carb where the boot touches the motor.




I had noticed a slight leak around just the closest carb on the picture and thought it was the bowl gasket which is being shipped to me right now.

I know I am going to need to pull the tank off and look for where the leak is coming from. Any suggestions.

My buddy thinks it may be the vacuum petcock is stuck. His suggestion was to crimp off the fuel line, drain carb bowls, and then try to turn it over in order to put pressure on the petcock and see if it will come unstuck.

How do your floats work? A stuck float could cause fuel overflow but since fuel is only sent to the petcock when the bike is on (unless you left it in PRI for some reason) this doesn't seem very likely.


Did you leave it on PRI?

No the bike was in the regular ON fuel position.
I did leave the choke on last night from when I cranked it up to move the bike.The motor was on around ~1 minute. Leaving the choke 1/4 of the way on overnight should not be the cause.
I took off the choke and started to drain each carb assuming that if the vacuum petcock were working properly the carbs should drain in a reasonable amount of time. After over a minute of the carbs still leaking at a steady pace I determined the vacuum petcock must be letting the fuel pass by when it should not, it was in the ON position.
I Checked to make sure there was no gas in the air intake box. Turned off the fuel under the tank. Drained the Carbs. Rinsed off the bike and moved it. Then Tried to turn it over a few times and the motor was gas locked. I then unplugged the coils, took out the spark plugs, and then turned it over until the gas was out of the motor. I Took some oil put a few drops inside of each cylinder head, threw the plugs back in and turned it over a few times, just to help keep the cylinder walls clean in her down time.

Now I am planning on getting a new vacuum petcock, doing an oil change, and changing the plugs. Does this sound about right?   
The petcocks are not interchangeable between the years are they? 

There was a thread on here about swapping the vacuum petcock with a non-vacuum operated one from a CRF 250X.  As I remember, the poster just plugged the vacuum ports on the carbs.

Quote from: 02GSNewb on November 20, 2011, 04:52:17 PM
I Took some oil put a few drops inside of each cylinder head, threw the plugs back in and turned it over a few times, just to help keep the cylinder walls clean in her down time.

Now I am planning on getting a new vacuum petcock, doing an oil change, and changing the plugs. Does this sound about right?   
The petcocks are not interchangeable between the years are they?

Sounds like you know what you are doing, shouldn't need to change the plugs though unless they were bad already. May be a damaged diaphragm in the petcock, you could replace it.

Well done GSNewb.  Not sure about interchangeability, but the later versions don't seem to suffer from the "fuel starvation" at high speed that the older ones have. Hopefully adidasguy can confirm wether you can use one of those.

One more thing to check would be your float needles and seats. If your floats, needles and seats were all working correctly, you wouldn't have had gas leaking everywhere and flooding the cylinders, even with a bad petcock.

Thanks for the advice guys! I am also planning on cleaning the carbs over the thanksgiving break. While they are off the bike I plan to replace the bowl gasket on the leaky one, and adjust the floats. I also plan on unplugging the mixture screws while they are off. Any suggestions / warnings will be greatly appreciated. 

While the new and old petcocks do the same thing, and could be interchanged, mounting a new one would be difficult. The new one is twice the size. One other difference is the fuel hose size. New ones have larger fuel hoses. You could grease the nipples and force on the older smaller hoses on a new petcock IF the hoses were were new and flexible. If you question the petcock, run in prime. If you still have a problem, it is not the petcock. (We have to remember that on old ones, prime is UP while the newer ones have prime in the middle position.)

I KNEW you had a definitive answer.  Thanks! 

Thanks for the input adidasguy. It would have been nice if I could have ordered just the diaphragm for the old petcock.  I decided to go with a new OEM petcock that is made for the 2001-2002 year, my bike is an 02. I got the petcock for $72 shipped which I felt was a pretty good deal. Again thanks for the advice.