Please help, technical difficulties

[Peachy]

I have a '04 GS500F and I have had it now for almost 2 months and since I bought it, it has been leaking gas off an on. It only leaks when it is stopped for a while and it leakes into the airbox and out the airbox over flow tube onto my garage floor! I have taken it to the shop for it several times and each time they can't figure it out and it stops doing it while it is their. This time they called Suzuki and they told them to replace the pitcock (sp?) not even sure if it is the correct word. It looks to me and my friends like it is coming out of the right carborator into the air box, but the maintence guys say the carborator is fine. Has this happened to anyone else??? :dunno: Any advice would be appreciated. Thanks

[The Buddha]

Yea bad petcock, and overflowing floats, happens and the airbox filling up is the result.
Cool.
Srinath.

[scratch]

Most likely the petcock setting is the culprit. Is it on PRI? If so, that may be the prob, as that is the selection that bypasses the vacuum operated diaphragm that only allows fuel to flow past when the bike is running; PRIme is the gravity feed selection for when your carburetors don't have any gas in them (like when you take your carbs apart, or drain them for storage). In prime, the only thing keeping gas from flowing is the float needles in the carburetor float bowls.

Oh, yeah, and Welcome to the site!

[perfdrug]

i must interrupt and say i'm impressed that the dealership took the inititive to call suzuki and further troubleshoot. i doubt my car dealership would go that far if the problem couldn't be repeated at the dealership. i bought my bike from a third party, but i've dealt some with my dealership when i replaced the head gasket, and i'm definatly going to be getting a bike from them, if i get a suzuki after this.  

[Peachy]

Thank you for the quick responses ! It's not set on PRI and when I bought it the dealership told me not to mess with that setting so I haven't even moved the nob. What causes it to leak setting still though? This is my first bike and I'm completely new to a carborator. Thank you very much for all the help

[Kerry]

I need to type faster!  By the time I show up, you've already got lots of responses.  Oh well - sorry for any duplicate info.

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What position do you leave the petcock in when the bike is stopped?  If you leave it in the ON or RES position, then the petcock may indeed be faulty.

But that's not the whole story.  Even if you leave a good petcock in the PRI position (or a faulty petcock in the ON or RES position), only a problem in the carbs will allow the fuel to leak out to the airbox.

To save some typing I'm gonna copy-and-paste an overview I wrote up for someone else recently:

Item 58 [in this diagram] is the lower T-connector I mentioned in my previous PM, where the fuel hose from the frame-mounted ON/RES/PRI petcock is connected. Fuel flows from here through an "item 57" to one of the carb bodies.

To drop into the float bowl the fuel has to pass through item 33, the float needle valve. (See the two metallic parts in this carb rebuild kit.) The lower half of item 33 (the silver-colored part) is pushed up by the float (item 28 ) as the fuel level rises in the float bowl (the large unnumbered item between the numbers 25 and 27). When the valve needle (silver-colored part) rises high enough it stops up the hole inside the valve needle seat (brass-colored item, upper half of item 33) and fuel stops flowing into the float bowl.

As the engine runs, fuel is sucked from the float bowl up into the carburetor body through the pilot and main jets (items 19 and 31 respectively). As the fuel is sucked out of the float bowl, the float will drop again and open the needle valve to allow more fuel in.

With that background, you can mentally "reverse engineer" what will happen when one or both of the needle valves are cracked open.

Why might they be "cracked open"?

1) Debris in the fuel system could be lodged between the tip of the valve needle and the valve seat.
2) The rubber tip of the valve needle could be worn or damaged (unlikely in a brand new bike, but possible, I guess):

[/list:u]Make sense?

You may just need a good carb cleaning, with special attention paid to the valve seat and needle.
At most you will need to replace those 2 parts.  (I'm talking about parts internal to the carbs.)

EDIT: Changed link from sisna.com to bbburma.net

[werase643]

Kerry,
we really appreciate your insight....BUT!!!! read the question....they have a 2004 bike....2 months old
i doubt the needles are dead

just kiddin, we still luv ya :kiss:

[Kerry]

Yeah, I knew that the bike was a 2004.  That's why I said

2) The rubber tip of the valve needle could be worn or damaged (unlikely in a brand new bike, but possible, I guess):

But I can't think of ANY other reason for the fuel to overflow the bowls.

So, let's say the right-hand needle is damaged (during assembly?) rather than worn....

[ollie357]

They told ya not to mess with the setting? Thats what a petcock is for when you're low on gas.

[Peachy]

Kerry thank you for the very detailed explanation...I needed that !!! I am a visual person so the pictures helped very much! I leave it in the ON position all the time, I know the RES is there if I needed, but when I asked the mechanic where I bought the bike he said don't mess with the PRI ! I think that is pretty much what Suzuki is thinking about the bad petcock. I took it in last week and they checked the carborator and flushed out all my lines to make sure there was no debre in there. They checked for oil in the gas or gas in the oil I'm not sure which one, but they were not mixed or anything, so I guess we shall see when the new petcock comes in ! THANK YOU VERY MUCH FOR THE HELP!!! !!! :mrgreen:    :mrgreen:

[perfdrug]

will that carb rebuild kit work with a 96? if not, where can i get one. i'm planning on taking the carbs 100% apart in an effort to learn even more. (plus i'm running pretty lean since my head gasket replacement, so i need to check the floats and pilots anyways).

[Kerry]

will that carb rebuild kit work with a 96?

Yep, it will work on all models from '89 to '00.  The carbs changed in '01.