Carbs leaking LOTS of gas

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Pack of 6 darn... Anyone have spares? $10 I got for one lol

Ok' I dont know if it's the spring, I'll take a video later today and post it up, you guys can tell me lol. I'm going to take it apart and clean up everything again.

Typically it's not the spring, just gunk or varnish making the needle not move properly. give it a good cleaning before you go out and replace anything.

Carb problem. Videos attached

Okay, I've fought this battle before

make sure you check that the brass overflow tubes in your bowls do not have any cracks in them, in addition to the other things suggested here. The easiest way to check is to take a fine grit sand paper and sand the outside of them by grasping the brass tube with the sand paper and spinning the bowl around on the tube. BE CAREFUL! Spray a bit of carb cleaner on the tube and the crack will jump right out (if it is cracked). If they are cracked you willl need to solder the crack shut. If you break it off you will..... probably have to yell a bunch and then log on to ebay

Whatever you do do not plug off the overflow with the solder. This will cause your bowls to 'vapor lock'

Good luck

jason8887 wrote: Okay, I've fought this battle before

make sure you check that the brass overflow tubes in your bowls do not have any cracks in them, in addition to the other things suggested here. The easiest way to check is to take a fine grit sand paper and sand the outside of them by grasping the brass tube with the sand paper and spinning the bowl around on the tube. BE CAREFUL! Spray a bit of carb cleaner on the tube and the crack will jump right out (if it is cracked). If they are cracked you willl need to solder the crack shut. If you break it off you will..... probably have to yell a bunch and then log on to ebay

Whatever you do do not plug off the overflow with the solder. This will cause your bowls to 'vapor lock'

Good luck

We'll I took off the bowl and filled it with gas to see if it leaked. I didn't see anything.

Clean the valve and the seat it goes in with something soft. A hard wood dowel works well if you can get one the right size.

It's also possible the floats are binding on th sides of the bowl, but unlikely unless they have been messed with.

Also, fuel height could be too high which would cause constant overflow - check your manual on adjusting.

DoubleDub wrote: It's also possible the floats are binding on th sides of the bowl, but unlikely unless they have been messed with.

Also, fuel height could be too high which would cause constant overflow - check your manual on adjusting.

I am thinking I need to adjust them... I held the floats up while U poured gas into the line and I had no leaks, so I can assume its the fuel height. I'll try youtubing it, no manual.

1. Find, buy, steal a manual.
2. Still could be the needle binding when the float isn't all the way up, in fact it still probably is.

DoubleDub wrote: 1. Find, buy, steal a manual.
2. Still could be the needle binding when the float isn't all the way up, in fact it still probably is.

which needle?

I don't know if your gas tank's petcock has one hose coming out of it leading to the carbs, or if it has two hoses.

If you look at the back of your petcock and it has 2 hoses, follow where they go, and here's what you'll probably find:

1) one of the petcock's hoses goes to a 'T' that then sends gas to each carb

2) and the other petcock hose goes to a nipple, a single nipple, on one of the carbs -- or the hose goes to a nipple on one of the hard rubber intake manifolds between the carb and cylinder.


If you look at your petcock and you find that it has 3 positions:
- 'Prime'
- 'On'
- 'Reserve'

then you have no 'Off' position selection on the petcock, and therefore you *must* have 2 hoses on the back of the petcock, because that hose (2) above is a vacuum line that sucks open a rubber diaphragm in the petcock when the engine is turning over, which allows the petcock to flow fuel to the carbs in the (1) hose above. In other words -- this type of petcock is OFF by default, there is a rubber diaphragm inside of it that stops gas flow out of the petcock. Until the engine turns over, and a vacuum on hose (2) above pulls open that diaphragm.

This is a 'vacuum-actuated petcock' if it has no 'Off' position -- the diaphragm, without engine suction on it (when the engine's off) -- is *supposed* to shut off fuel flow from the gas tank to the carburetors.

In other words:
- Engine turning over? Hose (2) routs engine suction to the petcock diaphragm and that opens the petcock and lets gas flow from the tank, and then fuel flows into the carbs in hose (1)

- Engine not turning over? Hose (2) goes limp, no engine vacuum on it, so the petcock diaphragm flaps shut, and no gas flows -- *UNDER NORMAL CONDITIONS*.

About 3 weeks back I bought and installed a petcock rebuild kit for my Kz650 1981 bike. Why? Well my carb overflow tubes were leaking just like yours (my Kz650 has a vacuum petcock like described above).

My carbs were still receiving gas from the gas tank WHEN THE ENGINE WAS NOT TURNING OVER. That told me that, with a continuous un-interrupted flow of fuel -- the dang petcock must be running overtime. My bike was off, yet my carb overflow tubes were flowing constantly a stream of gas.
So I figured that the petcock did not turn off like it's supposed to when the engine is turned off.

There is no 'Off' on this type of petcock. The rubber diaphragm is *supposed* to be the 'Off' switch in this type of petcock, but on my bike, gas kept flowing from the tank.

I'm not saying you need to rebuild your petcock, but that it *might* be the cause.

It's easy to check. Here's how I found out my petcock was bad:

- I pulled all the hoses off the petcock when my gas tank was about 3/4 full and made sure the petcock was in the 'On' position. Again, if you have a diaphragm-style petcock, there is no 'Off' setting on the face of the petcock, and even when the petcock says 'On', with no engine vacuum -- the petcock will shut OFF.

So with no engine vacuum sucking my petcock diaphragm open after I yanked all the hoses off the petcock -- I shoulda seen no gas flow out of my petcock, and yet with all tubes removed, petcock in the 'On' position, I had mucho gas flowing from the petcock. That meant the diaphragm was NOT SHUTTING THE GAS OFF, wasn't doing its job. With the engine Off the petcock kept flowing gas, and it overfilled my float bowl and ran out the overflow tubes.

I bought and installed a petcock rebuild kit for my year/model Kz650 (I'm sure they make them for your bike too) and to test if the rebuild kit fixed my problem, I put the petcock to 'On' with 3/4 tank of gas -- nary a drop of gas came out of the newly rebuilt petcock. That's the right situation on a vacuum-operated petcock: no engine suction? IGNORE WHAT THE PETCOCK SAYS, if it says 'On', or if it says 'Reserve,' the petcock is still OFF with the engine not running.

(However, if you put your petcock on 'Prime', it bypasses the diaphragm and allows gas to flow -- that makes it so you can fill your carbs up with gas after you drained all the gas out of them for, say, a carb clean.)

I hooked up the gas line and vacuum line to the petcock, and the bike ran fine, and no more overfilling of the carbs, the petcock rebuild kit STOPPED the gas from constantly running out of my carb overflow tubes.


Reason I brought this up is -- I noticed in your video:

- your bike's engine was off

- and yet you had a running stream of gas from the overflow tube there

- and when you went to tighten the drain screw, I did not see a dripping from the drain screw, so I thought "the drain screw and its o-ring are probably not the issue."

EASY TO CHECK THIS.

1) does your petcock have 'On' and 'Res' and 'Prime' but no 'Off', with an extra rubber hose running to an intake manifold or to a single carb? If so, it's a vacuum petcock.

2) so pull all hoses off your petcock and put it in the 'On' or 'Res' position -- NO GAS SHOULD EVEN DRIP or run out of the petcock.

3) but if gas is still coming out, rebuild your petcock (or if you're cheap, try a petcock clean first).

Good luck. That dripping gas hurts man, 91 octane in California is between $4.75 and $5 a gallon now.