ZG1200 Persistant Fuel Leak: Carb Overflows

I know this isn't really a KZ question (my kz project is on hold for the moment until funds allow!), but I have come into a free Kawasaki Voyager XII (zg1200) by way of a friend. Not really my style, but the price was right so I picked her up.



before


Classic "ran when parked" condition, but sat filled with fluids for 6 years. Jumped it from my car to try and start it up just for shits and gigs, and when I turned the key to the on position i heard the fuel pump click on and it just started pissing gas out the carb overflow.

SO, no big deal, I figured the obligatory carb cleaning would do the trick and unstick those float valves, so embarked on what i thought was routine maintenance, but turns out on these bikes is something more comparable to open heart surgery :pinch:

The "gas tank" is a dummy housing for the air cleaner and battery and the real fuel tank is under the seat, so just to drain the tank and clean the carbs means removing all the bags, the luggage rack, both seats, shocks, and the whole rear subframe. This thing is no joke.



after :sick:

ANYway, I cleaned the carbs and put them back on, intake manifold back on, and gave her another go at a jump start. Same thing, still leaking out the overflows. Also, when I punched the starter, it pulled voltage but didn't turn over (good solenoid, bad starter?)

What do you think I should try next? I was really trying to avoid buying a whole carb rebuild kit for this thing cause I wanted to get it running as fast as possible on the cheap. This is turning into a bigger project than my project bike!! grrr

You guys have bailed me out more than once when I was in over my head. Any thoughts?

Appreciate it

Just thought i'd add that when I cleaned the carbs I thought the float valves looked good to me, but this is only my second carb rebuild and I'm no expert. I actuated the float levers manually and they all moved fine, even before cleaning, and the spring action of that little nipple piece was also free and clear

Does anyone have any tricks for cleaning pesky float valves that don't wanna work?

Also, I used a carb cleaning spray, brass brush and rags, not a dip, and I didn't replace any rubbers/gaskets (they all looked good and were soft, plus I'm trying to be cheap! Why do free bikes never stay that way? my first bike was a '76CB500 Twin I got for free. It took over $400 to get it running.. on kick start only- shoulda just bought a runner with a title!! )

Be vary careful here, as these Carbs do not have an overflow tube installed. These will overflow fuel into the engine, thus hydro locking the motor, possibly bending a connecting rod. Common problem with that series carb.
Go to the Zg/GTR forum and you will see, www.zggtr.org/index.php
You need new float valves/ carb kits, then set the Wet Fuel Level in the bowls. I would also recommend doing the Overflow tube modification, as I have on my ZG1000, which has the same carbs.
If you search on the ZG site there will be an explanation of how to do it, or I also posted it here under my Concours resurrection thread. A bit of bras tube from the hobby store, and a correct drill bit to provide a slight interference fit, will install overflow tubes. But you need to Control the Fuel Level First and Foremost.

Have you checked/cleaned the fuel tank?
I had a problem with my carbs overflowing as well, but after I cleaned the tank and installed new fuel filters, there was no more leakage. Tiny specks of rust/gunk were clogging the float needle.

Motorhead, the carbs do have overflow tubes. That is where they are leaking from. I'm not sure if they have been modified to have them or if the carbs have been replaced or what, but they do have them. The bike is a 1992 if that makes a difference. The carbs are Keihins, ill check the exact model next time im in the garage.

Despite the overflows, I am also worried about hyrdolocking because the carbs fill up at such a rate that fuel is rushing out the overflows but the fuel level within the carbs is still rising to the point where it fills the carbs entirely and begins to come up the breather hoses in the top of the carbs. At this point there must be fuel in the cylinders, so when the carbs come off I will allow time for the fuel inside the engine to evaporate. (could that be why the starter drew voltage and didn't turn the engine over? :S YIKES

I have not cleaned the fuel tank, I just drained the old fuel, rinsed it by sloshing around some fresh fuel in there, and then filled it with new gas.

I also did not replace the fuel filter. I will try that first because I already have some fuel filters lying around so its free!

So my to do this week is to clean the carbs again, clean the tank, and replace the fuel filter. I guess its possible that is the problem because it didn't start leaking immediately like the first time I tried to start it (before the cleaning). It took about 20 seconds before the leaking started after the cleaning, so I don't know if thats just how long it takes to fill the float bowls and my float valves are garbage, or if thats the amount of time it takes to fill the float bowls and re-clog the float valves. I guess I'll find out!

I guess if that doesn't work I'm looking at a REAL carb rebuild where you replace parts and what not.

Thanks for your suggestions Motorhead and Jona Barish!

If the float valves are all metal (no rubber tip) you can lightly sand them with 1000 grit paper. Just squeeze the needle point in the paper and twist it a bit. I've cleaned up a few like this.

Looks like a f-ing mess!

You should bench test the carbs before you put them back on. Set them in a vice and attach a makeshift "gas tank" to make sure they are working before you go throw all that junk back on.

The bike is sweet though. I want one just to cruise 2-up with the old lady. But I need to find one like that one...free. lol

With some carb designs, it's possible to reassemble the float mechanism upside down, not that any KZr member would ever do that. :lol:

Good Fortune!

HolyKAW wrote: I know this isn't really a KZ question (my kz project is on hold for the moment until funds allow!), but I have come into a free Kawasaki Voyager XII (zg1200) by way of a friend. Not really my style, but the price was right so I picked her up.

Attachment IMG_20121127_234614.jpg not found

before


Classic "ran when parked" condition, but sat filled with fluids for 6 years. Jumped it from my car to try and start it up just for shits and gigs, and when I turned the key to the on position i heard the fuel pump click on and it just started pissing gas out the carb overflow.

SO, no big deal, I figured the obligatory carb cleaning would do the trick and unstick those float valves, so embarked on what i thought was routine maintenance, but turns out on these bikes is something more comparable to open heart surgery :pinch:

The "gas tank" is a dummy housing for the air cleaner and battery and the real fuel tank is under the seat, so just to drain the tank and clean the carbs means removing all the bags, the luggage rack, both seats, shocks, and the whole rear subframe. This thing is no joke.

Attachment IMG_20121201_135921.jpg not found

after :sick:

ANYway, I cleaned the carbs and put them back on, intake manifold back on, and gave her another go at a jump start. Same thing, still leaking out the overflows. Also, when I punched the starter, it pulled voltage but didn't turn over (good solenoid, bad starter?)

What do you think I should try next? I was really trying to avoid buying a whole carb rebuild kit for this thing cause I wanted to get it running as fast as possible on the cheap. This is turning into a bigger project than my project bike!! grrr

You guys have bailed me out more than once when I was in over my head. Any thoughts?

Appreciate it

Those road sofas are really dangerous to ride. Your best bet is to pack it all up in a big box and call me. I'll come and dispose of it properly for you.

If you really want to risk your life with that thing, get good advise at the American Voyager Association website or the abbike board.

The fuel pump is NOT supposed to run when the engine isn't running except when the starter is cranking. IOW you have an electrical problem with the starter circuit. The pump has points in the end cover that close when the fuel pressure drops so the pump doesn't run continuously. If it does run continuously it's over pressurizing the cabs and blowining the float needles open.I would start looking there. Maybe a bad starter relay. Get a FSM (factory service manual).
On either of those websites you can get contact information for a gentleman named Carl Leo. He is THE Voyager guru. He knows these bikes inside out and backwards and loves to help. Buy some parts from him if you feel guilty about all the free help he gives you.

You really got into that thing. I think the carbs will come off without taking the rear end off, but its too late for that now. I know the fuel pump will come out without taking the rear off even though the manual says not. It's just a little tight in there. Change the fuel filter when you get the pump out. Be careful connecting the hoses back up to the pump. Don't mix up the in and out hose. DAMHIKT. It's not intuitive. When you get it running good, enjoy it. It's a great long distance tourer. PM me if I can be of any help. I went thru mine last winter and know a little about them. There's more to do before you get it all together. High on the list is the electrical system. Pull all the connectors , clean and grease them with dielectric grease. Change all the fluids. Bleed the brakes and clutch hydraulics. You should know the drill. Good luck and have fun with it.

Either the parts fiche is wrong, or someone added the overflow tubes. Here you can see No Tubes coming up from the bottom of the float bowl. Other Keihin models do have the tubes and the bowls can be fitted to your carbs.



Even if the fuel pump does run all the time, it shouldn't cause flooding if the float valves are functioning correctly. That should be a low pressure pump, like 4-5 psi. The tips on the float valve needles will be a rubber type, Viton I believe. It may be that whoever added the overflow tubes have them installed incorrectly? Do they extend up above the Gasket surface of the float bowl to carb body? And if so how far? About 8-10mm? Also they could be loose, cracked or otherwise leaking. The Keihin CVK is a good carb for Stock application, delivering good overall performance with good economy.

For whatever reason -- unknown to me -- sometimes the carb parts diagram on kawasaki.com doesn't show overflow tubes, but the carb assembly diagram may show overflow tubes.

Where overflow tubes are fitted to carbs, the float bowl in the carb parts diagram imo ought to depict a slim brass overflow tube inside the float bowl.

And where carbs have no overflow circuits -- overflow tubes aren't fitted -- the float bowl diagram would imo not depict a slim brass overflow tube inside the float bowl.

Here's the carb assembly diagram:



Without being positive, would surmise from the carb assembly diagram that stock carbs on the bike at hand would have overflow circuits.

Good Fortune!

Thanks for your advice TomW, Patton, and Motor Head.

On Tom's suggestion I went over to the American Voyager Association website and they have a lot of great tech tips. They have a writeup on this page www.amervoyassoc.org/XIITipsBody2.htm on how to clean up the points on your fuel pump so I thought I'd start there.

When i got the fuel pump out and got a proper look at it, however, I realized it is not the stock fuel pump. Someone replaced the stock 4 wire fuel pump with a 2 wire fuel pump, and i think they may have messed up the wiring.



the PO's got the red from the 4 pin connector running into the blue/black of the pump, the green runs from the pump down and grounds to the crankcase

The fuel pump goes on as soon as I turn the key from ACC to ON, and goes off when I punch the starter. The starter also doesn't turn over, so I'm going to check the solenoid and look into that as well.

It is my understanding that the fuel pump should be off unless Im punching the starter button or the bike or it is running, correct?

But, would that explain my carb overflow situation, or as Motor Head said, should the float valves take care of the excess fuel delivery despite the pump acting up?

The way its shaping up, I think I have at least 3 issues to address
1. Starter solenoid, motor, or circuit
2. Fuel pump wired backwards?
3. Float valves/seats not sealing up properly

I found a PDF of the service manual here

Shoot those links were no good

American Voyager Association tips (fuel pump points near the bottom of the page)

Kawasaki Voyager XII manual