Thar' she blows.

Hey guys.
I've got a 79KZ shafty (VM28's) that I've yet to get running. When I hit the starter, I get gas squirting out what I think is a vacuum fitting. It's a brass fitting on #2 just above the air screw. To tell the truth I've not been able to figure out the purpose of that orifice anyway and there's no description of it in Clymer's.

After I boiled and cleaned the carbs, the float valve on #2 was sticking and the bowl not filling up. I removed the carbs, cleaned the valve and checked float levels on all 4 just in case. As far as I can tell the float bowl is filling up and not overflowing. From that I assume the float valve is not stuck either way.

Couple questions:
1) Any idea what would cause gas to squirt from that fitting?
2) Why is that fitting not present on #1?
3) Should the fittings on 2,3,4 be open or closed?
4) What the hell is that fitting anyway?

btw, I do not have a vacuum petcock.

Thanks ya'll.

That might be the carb over flow. Is there another one like it on another carb.

You probably have the float sticking on the carb. Roy

Thanks. The fitting I'm referring to is just above the airscrew on the carb body not the overflow tube which exits at the bottom of the bowl.

Where excess fuel is entering the float bowl for whatever reason, a clogged overflow circuit may allow such excess fuel to escape through the vent nipple.

The overflow circuit may be clogged anywhere throughout its passage, from the orifice at tip of overflow tube inside float bowl, to the end of the overflow hose which usually exits underneath the bike.

Sometimes crud gets inside the end of the overflow hose underneath the bike, or the hose tip gets gooey-soft and pinched together.

If not already done, would assure overflow circuit is clear and functional.

Good Luck!

[Click on image to enhance view]

Thanks Patton, yes it's the vent hose fitting in your pic with the arrow to it. Should that vent to something or just the enviornment?

I've honestly about had it with this POS carb. I cleaned it using the boiling lemon juice method followed by carb cleaner. Reinstalled and the float bowl never filled up. Took the carbs off (about the 15th time) and cleaned the valve. Checked levels with the carbs on a bench and they were perfect on all 4. Put carbs back on and now evidently the float valve is sticking open. Just checked level with carbs on the bike and its halfway up the throttle body. I'm sick of pulling the carbs off.

Going to Iraq in 2 months amd hoped to get this damn thing running. Doesn't look like that's in the cards. I'm fed up with it. Just one more damn thing to have to deal with.

Thanks for your help though.

Mortarmanmike wrote:

...it's the vent hose fitting in your pic with the arrow to it. Should that vent to something or just the enviornment?
cleaned it using the boiling lemon juice method followed by carb cleaner. Reinstalled and the float bowl never filled up. Took the carbs off (about the 15th time) and cleaned the valve. Checked levels with the carbs on a bench and they were perfect on all 4. Put carbs back on and now evidently the float valve is sticking open. Just checked level with carbs on the bike and its halfway up the throttle body. I'm sick of pulling the carbs off....

The two vent hoses exit to open air. Sometimes they are routed to exit underneath the seat as shown in the pic below. While others prefer routing them to exit underneath the bike.

Checked levels with the carbs on a bench and they were perfect on all 4 --- indicates that all four float valves were functioning properly, at least momentarily on the bench. Valves had to open to allow fuel entry into bowl, and then close to halt fuel entry when correct fuel level was reached. Also indicates that all four floats were properly functioning.

Put carbs back on and now evidently the float valve is sticking open. Just checked level with carbs on the bike and its halfway up the throttle body --- indicates not only excessive fuel being allowed into carbs (for whatever reason), but also that the overflow circuit is malfunctioning. A correctly functioning overflow circuit will permit excess fuel to escape (usually via a hose routed to underneath the bike) before such excess fuel can rise up into the carb throat.

Excess fuel being allowed into floatbowl typically results from a faulty functioning float valve (eg., dirty or worn or mismatched needle or seat), or a fauly functioning float (eg., improper tang adjustment or leak or lost buoyancy or installed upside down or sticking or bent or broken, etc.)

When first starting engine with freshly cleaned carbs, sometimes one or more float valves leak. Often, while engine is running, the valve may be jolted into leak-free action by rapping repeatedly against the float bowl with a plastic mallet or large screwdriver handle.

If not already done, would sniff-test crankcase oil and physically examine its condition, all to assure lack of fuel contamination in the crankcase. When in doubt, would change oil and filter. A correctly functioning overflow circuit is supposed to prevent potentially disasterous fuel intrusion into the crankcase.

When re-attaching carbs to engine, remember to connect the throttle cables before aligning the carbs with the holders. It also helps to lube the holders and carbs with silicone or Armorall before pushing the carbs inside the holders. I use a wooden stake to lever the carbs into the holders, and they just squish right into place.

An extra-long Phillips head screwdriver is also handy to easily reach the inside clamp screws.

Good Luck!

Pic is from 1976 KZ900-B1 LTD.

[Click on image to enhance view]

usally when you get fuel pouring out of the bowl vent's it is caused by bad needles and seats ( float valve assemblies) when you replace them it should solve your problem most times you will find grooves worn into the tip of the needle double check your oil level as gas from the tank go straight thru the throat of the carb and into the crankcase when this happens not all of it will hit the floor. if there is gas in the oil dump it a nd start over fresh.

Would always install a fresh in-line fuel filter before allowing any fuel to enter a freshly cleaned carb. If bike has dual fuel lines, use two in-line fuel filters.

Many a freshly cleaned carb has been instantly sullied by an initial onslaught of non-pristine fuel.

Good Luck!

Thanks guys, for comfirming my suspicions. Haven't checked yet but bet there's oil in the crankcase. It just doesn't make sense. Fresh gas, new fuel filter, cleaned valves, checked float level. Ugh...

I'm almost convinced that God does not want me to ride this bike. Think I'm just gonna replace the oil and park it in the garage for the next year. I'm tired of pulling and replacing carbs. This bike has done nothing but wear on my patience since I got it.

Once again, thanks for your help. Keep your eyes on the classified section in about 15 months. I'm wondering what a demon-possesed KZ goes for?? <joke>

Don't mean to hijack this thread, but while we are on the subject of vents...

I've got VM26S's on my KZ1000. I leave my bowl vents uncovered nad I sure seem ot get a lot of vacuum/airflow thru them. Is that normal? If I cover them it acts just like closing a vacuum leak, some time air flows out of them too... The problem is most pronounced on #3 carb. Number 4 has very little flow, as does #2...

What am I missing?

thx!

Silly question perhaps, did you blow out all orifices with compressed air?

You'd rather have your overflows working instead of the gas filling up the carbs then running across the intake manifolds then down the cylinders into the crankcase.

If you blow out the carb passageways with compressed air after you've soaked them, and maybe slide a metal guitar string in the smallest orifices (gently though), then
it's less off-and-on with the carb removal dance.

Me? I'm taking week or several days off and lots of physical exercise and random outbursts. Then I'm coming back to it with compressed air. And prior to the weeklong layover I'm ordering/or buying at the local Kaw dealer:

- a set of float needles and seats (aka 'jet kit')

- *and* I'm using a small bowl of gasoline to verify all 4 of my floats are good, ie. not cracked, by trying to submerge the float in the gas and verifying they don't fill up with gas and sink to the bottom.

Then you can retry with a good starting point:
- floats are *known good*
- new float seats and float needles
- blown out passageways in the carbs
- remove any rubber tubes from the overflow outlets
- test that each overflow outlet WORKS on each carb
by reassembling without the float in
the carb, fill one carb at a time with gas, then
make sure the overflows are WORKING. That way
you avoid: squirting gas out the vents
and gas filling up the carbs then traveling from the
carbs across the intake manifolds into the cylinders and down into the crankcase.

The several days or week off, with all the needed parts (jet kit or float valve/needles, perhaps new a new float or 2 if needed) on order for when you're more optimistic.
I just get away when I'm frustrated, it *works.* Gives you a new perspective on this-n-that.

Good luck.

I mean the thing is, it sounds like it's real close.