Please help me identify what is leaking on my carb. My bike is a 2002 gs500. It was running great and then one day when I tried to start it, fuel came dribble out of my carb.  It's an exposed nipple that is pointing down just in front of the bowl and it's only on the left side. I had never noticed it until it started leaking so I don't know if it's supposed to be exposed or capped or attached to something else. Thank you for any help!

Sounds like your floats are sticking, run some seafoam in the next tank and if that don't fix it pull the bowls and clean


Sent from my iPhone using Tapatalk

Pic would help here, but... My first thought from your description was the carb bowl drain.  There is a screw that opens and closes that nipple (one on each carb in fact).  Try tightening that screw and report back. 

- Bboy

Edit: Check this thread to help figure out what part you are referring to.
http://gstwins.com/gsboard/index.php?topic=56601.0

just in front of the bowls may be a missing mixture screw; if it's a nipple on the bottom of the bowls, then it's the float drain nipple.

Here is a pick. It's not the bowl drain. You can see here it's about to drip. It's only on the left side. Thank you for the responses!

[attachment deleted by admin]

For some reason, I don't recognize that at all - but it definitely does look like a hose should be attached to that... You wouldn't happen to have a California model would you? - In which case, there's an extra hose that attaches on the bottom of each carb and connects to each other with a T...  Not exactly sure what those CA hoses do - I have a guess, but I'll keep it to myself for now lol.

- Bboy

Here is a pic that shows CA model carbs with the extra tubes...



Here is a pic that shows... uh, the rest of us?... with those tube connections plugged instead of a nipple for hoses... the black plugs to the left of the mixture screws



- Bboy

I'm not sure how to tell if it's a California carb or not. The carbs are connected to each other and then a T goes straight down from there. I'm pretty sure this is an overflow rout correct? I've looked all over and can't seem to find what I have here. Thinking maybe the PO put two different carbs together if that's even possible.

My thinking was that the CA hoses rerouted overflow that normally goes into the airbox and drains out, but I dunno for sure.

- Bboy

Ok sorry, I posted my response before I saw you picture. It does look like I might have half a California and have regular. If that is the case does anyone have an idea of what to do?

I suppose that's possible, though I hear separating the carbs is a chore to be avoided - so its just not a commong thing to do at all.  We could use some confirmation on what those CA hoses actually do.  If it is overflow that normally goes to airbox drain, then you have an issue in that carb - maybe, float is too high, or needle valve is not seating properly... something to that effect, which you might need to open the carbs to find out or clean them.  But! I would confirm what those CA connections are for first.

- Bboy

Quote from: BockinBboy on April 24, 2014, 01:04:48 PM
We could use some confirmation on what those CA hoses actually do
...
But! I would confirm what those CA connections are for first.

Looking at the service manual, the tank breather/vent feeds into a canister under the battery box, where it gets mixed with fresh air (from the battery box) and fed to the bottom of the carb bodies to be drawn into the engine.  It looks like the CA model evap ports on the carbs do not tie into the channels for the pilot, choke, etc and as such should not have fuel coming out of them; in fact there should probably be a slight vacuum there to help draw the fuel vapors out of the canister.

Oh I see, so flow was opposite direction than I had been thinking.  So, yeah, fuel should not come out of it then... should only go in if it were connected to the tank vent through a canister properly.  So, in light of this, I would get rid of any CA crap that might be on there.  If the bike was a CA model, I'd check to see where the tank vent is routed.  If tank vent is routed into a canister under the batter box, I'd take out the canister and route the tank vent to the ground on the right side of the bike, on the bottom frame, under the right rear brake lever... then I'd cap off that CA nipple on the carb.  If tank vent is already routed down the bike near the rear brake lever, and there is no canister under the battery box, then I'd just go ahead and cap off the CA nipple on the carb.

- Bboy

Yep, that's a CA model, I have one. Mine had the nipples plugged until one decided to fall out, then it got plugged with a set screw instead.

It should hook into the EVAP can. My bike has a hose routing diagram under the seat on top of the fender showing how it all hooks up, not sure if yours would still be there.

just get a nipple plug. I used to have the hoses on mine but i pulled and plugged them cause it was causing a vacuum leak. it is mostly just for smog i believe

Thanks everyone! I cleaned the carbs and pluged that nipple up and it seems to be working just fine now. She wants to stumble a little before getting going in the low gears and backfired a couple times after a long ride on the freeway yesterday. I'm thinking the old fuel that's in the tank could be causing this.

Old fuel, the stuff you cleaned them with etc etc all can do that.
Cool.
Buddha.