flooding carb while on sidestand

hi everybody i finally got some life out of my kz650-79-it took alot of screwing around but i got it to idle after cleening the carbs-newplugs-new pods and went up 2 sises to accomadate the pods-now the bad news when i have it on the sidestand it leaks fuel from the carbs [mainly #1]does it sound like a petcock issue?when its on the center stand leekege is minimal-this bike sat for a long time [maybe 10 years]before i bought it.also i belive im missing some vac lines from the carbs [ihave the 2 pieces just not sure where they go[2 pieces aprox 8 inches long]i got rid of the rest of the lines when i went to pods.-last thiong -what petcocks are interchangable with a 79 kz 650..thanks ...mike

irish mike wrote:

hi everybody i finally got some life out of my kz650-79-it took alot of screwing around but i got it to idle after cleening the carbs-newplugs-new pods and went up 2 sises to accomadate the pods-now the bad news when i have it on the sidestand it leaks fuel from the carbs [mainly #1]does it sound like a petcock issue?when its on the center stand leekege is minimal-this bike sat for a long time [maybe 10 years]before i bought it.also i belive im missing some vac lines from the carbs [ihave the 2 pieces just not sure where they go[2 pieces aprox 8 inches long]i got rid of the rest of the lines when i went to pods.-last thiong -what petcocks are interchangable with a 79 kz 650..thanks ...mike

Is the fuel leaking from the overflow tubes or from the pods?

Likely results from excessive fuel getting past float valve, for whatever reason. And if dripping from pods, overflow circuit may be clogged or overwhelmed (some carbs don't have overflow circuits). This problem could exist in one or more of the carbs.

Where overflow circuit is properly functioning, usually the excess fuel inside the floatbowl dumps out underneath the bike from hoses attached to the nipples on bottoms of floatbowls.

Where overflow circuit is not properly functioning or doesn't exist, the excess fuel may rise on up into the carb throat and flow both ways, forward toward the engine and back toward the airbox or pods.

Fuel collecting in the airbox may drain straight down into the crankcase through the s-shaped rubber hose connected between the airbox and crankcase vent (where so fitted). This isn't an issue with pods, where fuel escapes by dripping from the pod.

Fuel flowing toward the engine may enter the combustion chamber and drain down past the piston/rings into the crankcase.

Fuel may have gotten into the crankcase and contaminated the oil. Would sniff-test and examine physical condition of oil. Sometimes evidenced by a "rise" in the observed oil level.

If crankcase oil has been diluted with fuel,would not start engine until changing both oil and filter AND correcting the carb issues.

Meanwhile, would detach fuel line from petcock, to assure no more fuel can reach the carbs.

As known, fuel contaminated crankcase oil may result in cata$trophic engine failure.

Am thinking subject carbs are manual slide. Here's a pic that might be helpful.

Manual petcock has no vac tube.
Vac petcock needs vac tube from carb, which may come from one of the carb holder nipples or a separate 5th vac nipple as shown on the pic.

If not already done, would also install an in-line fuel filter before any fuel is allowed to enter freshly cleaned carbs.

Good Luck!

my carbs do have the overflow circut the gas seems to drip from the overflow nipple mainly when the bike is tilted .or on the sidestand.i really didnt want to take the carbs off again but i gotta do what i gotta do.ikinda thought it had something to do with the pet cock being it mainly happens the bike is tilted to the petcock side on carb #1.thanks again you have been agreat help[now i know where those vent hoses go]still cant keep it idling long enough to do any type of syncing,....thanks mike....

irish mike wrote:

my carbs do have the overflow circut the gas seems to drip from the overflow nipple mainly when the bike is tilted .or on the sidestand.i really didnt want to take the carbs off again but i gotta do what i gotta do.ikinda thought it had something to do with the pet cock being it mainly happens the bike is tilted to the petcock side on carb #1.thanks again you have been agreat help[now i know where those vent hoses go]still cant keep it idling long enough to do any type of syncing,....thanks mike....

Am not suspicious of petcock. Because petcock, manual or vacuum, functions same regardless of bike being parked on side stand or centerstand.

Before again removing carbs, would verify correct floatbowl fuel level with the clear tube test. This to confirm the fuel level isn't too high and escaping from overflow circuit when bike is leaned to the left. Supposed to be 2~4mm below bottom of carb (see photo below).

Could also experiment by parking with bike leaned over to its right side. To determine whether same problem exists.

Are overflow hoses fitted? This to confirm the leakage is actually dripping from end of the the overflow hose underneath the bike.

Sometimes the leak is from elsewhere, such as a cracked fuel line, loose fuel line connection, defective floatbowl gasket, loose fitment of floatbowl to carb, slightly deformed ear on bowl where screw attaches bowl to carb, or cracked overflow tube inside floatbowl, loose drain screw, damaged drain screw o-ring, or a loose fuel pipe joint.

Good Luck!

[Click on image to enhance view]

I have said this before and it works. Pull the drain screw and have a little cup to catch the gas when it pours out. There may be grit or rust or something in the carb that will come out when you "flush" the carb by removing the screw.

After that has been completed, take a soft rubber mallet and whack the number 1 carb a couple of times. That will usually unlodge a stuck float in the carb and thus stopping the overflow problem.

I had that same problem on #1 and #4 on separate occasions (about 6 months apart). Follwed this advice (that someone else gave me) and it has never occured again. Guess what - the bike runs great to 115 mph, does not leak when riden or parked and I have never had to pull the carbs multiple times.

Do check the oil with the sniff test and do get an inline filter. Frigging with carbs always causes more probems then what they are worth. Try a low tech approch and when all else fails then pull them.

My Low tech 0.02

KR