Carb or Petcock Fuel Leak Question (Z750 Twin)

Guys, quick question. Im not used to gravity feed fuel taps that we have on our bikes at all so i was just wondering if they are left in the 'on' position should there be some fuel leakage? Im finding some fuel build up under the carbs in the oil pressure sensor area.

If thats not the petcock what might it be??

If the fuel floats/valves/needles etc are all in perfect shape, they will not overflow.... at least not any noticable amount. That said, you should always shut off the petcock when you park it for any length of time. Many will leak gas.

bountyhunter wrote: If the fuel floats/valves/needles etc are all in perfect shape, they will not overflow.... at least not any noticable amount. That said, you should always shut off the petcock when you park it for any length of time. Many will leak gas.

+1 If you look inside the original literature about the petcocks you will find thefollowing removable fold out provided by Kawasaki:

:laugh: Ed, have you turned off your petcock tonight & got that beer? :lol:

bountyhunter wrote: If the fuel floats/valves/needles etc are all in perfect shape, they will not overflow.... at least not any noticable amount. That said, you should always shut off the petcock when you park it for any length of time. Many will leak gas.

My floats are good, i'll maybe look about replacing my needle valves. Does that mean i'll need to reset my float height?

750steve wrote: ...My floats are good, i'll maybe look about replacing my needle valves. Does that mean i'll need to reset my float height?

Perhaps the float valves just need a good cleaning.

Replacing the float valve should not affect the float height or the fuel level.

Float valve and float must be properly operational in order to perform the clear tube test, which will show the fuel level.

If the fuel level is wrong, the float tang may be adjusted to achieve a float height that results in the correct fuel level.

Good Fortune!

If you think it may be the Petcock leaking. Try disconnecting the fuel line, and then running down into another container overnight.

Patton wrote:

750steve wrote: ...My floats are good, i'll maybe look about replacing my needle valves. Does that mean i'll need to reset my float height?

Perhaps the float valves just need a good cleaning.

Replacing the float valve should not affect the float height or the fuel level.

Float valve and float must be properly operational in order to perform the clear tube test, which will show the fuel level.

If the fuel level is wrong, the float tang may be adjusted to achieve a float height that results in the correct fuel level.

Good Fortune!

thanks Patton. i'll clean em 1st as they really did seem ok on close inspection, no wear at the taper & the spring was ok too. I even took a high res digital pic of them so i could enlarge the taper & look for damage/wear

Motor Head wrote: If you think it may be the Petcock leaking. Try disconnecting the fuel line, and then running down into another container overnight.

Definately not the petcock, i've already done as you said to eliminate it.

It sometimes helps to chuck a Q-tip in a drill and use it to clean the seat orifice.

And when reassembling the carbs, the same float needle should be kept with its same seat.

Good Fortune!

750steve wrote: Guys, quick question. Im not used to gravity feed fuel taps that we have on our bikes at all so i was just wondering if they are left in the 'on' position should there be some fuel leakage? Im finding some fuel build up under the carbs in the oil pressure sensor area.
If thats not the petcock what might it be??

Excess fuel getting past the float valve into the float bowl (for whatever reason) should escape through the overflow circuit, which usually exits from a nipple on the float bowl, and on through a hose routed to discharge underneath the bike.

Such fuel escaping via the overflow circuit should not build up under the carbs in the oil pressure sensor area.

Fuel accumulating in the oil pressure sensor area might be from a leaking fuel line, fuel line connection, ill-fitting fuel pipe (tee joint), carb bowl gasket, or overflow hose, or where overflow hose attaches to the nipple at bottom of the float bowl.

Persistent leaks past the float bowl gaskets may sometimes be stopped by using double gaskets.

The float bowl usually has ears with holes through which the screws attach the bowl to the carb.
On some carbs, if over-tightened in an effort to better seal a suspected leaking float bowl gasket, the ear may bend slightly and prevent proper tightening. In such case, the ear may usually be carefully straightened. Could try pressing the bowl down against a flat surface, and tapping the bowl to re-align the ear.

Good Fortune!

Do your carbs have the Brass overflow tube, pressed into the float bowl? These can crack, and leak out the overflow. It will lose most of the contents of the bowl with the petcock off.
Thinking related issue to your other thread maybe, www.kzrider.com/forum/3-carburetor/52967...ak-from-drain-screws