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Leaky Carburetors

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27 Jul 2022 12:44 #871138 by dancragin
Leaky Carburetors was created by dancragin
I have a bone stock,  restored 1976 Z900 A4. The carburetors were rebuilt completely with factory parts and the the bike runs perfectly.
Problem is when I store the bike. If I do not drain the carbs, or turn the fuel pepcock off a block before home and runs the carbs empty. They leak when 
the bike is stored.

The leak comes from the bowl gaskets. I figured maybe the float setting was too high, but even after adjusting all the floats dynamically with a clear hose like
the service manual states, they still leak. I tried different bowl gaskets and even sealed them with grease, but they still leak.

It does not make a big mess, as once enough fuel leaks out it stops, but its messy and does not seem right.

Is this normal?

Dan

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27 Jul 2022 12:52 - 27 Jul 2022 13:06 #871140 by zed1015
Replied by zed1015 on topic Leaky Carburetors
If the float valves are not leaking and the fuel is simply overflowing out of the carb mouths It's possible that the bowl flanges are warped due to overtighening in the past and only nipping up on the corners.
Lapping on a flat plate ( with a hole in for the brass overflow pipe to clear) may fix the issue.
Failing that you can buy Viton bowl  gaskets that are guaranteed to work.


 

AIR CORRECTOR JETS FOR VM CARBS AND ETHANOL RESISTANT VITON CHOKE PLUNGER SEAL REPLACMENT FOR ALL CLASSIC AND MODERN MOTORCYCLE CARBURETTORS
kzrider.com/forum/23-for-sale/611992-air-corrector-jets-





Last edit: 27 Jul 2022 13:06 by zed1015.

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27 Jul 2022 16:02 #871161 by Mikaw
Replied by Mikaw on topic Leaky Carburetors
You could try putting a 2x4 wood block under the side stand. I have always made it a habit to turn the Petcock off early and run the fuel level down when I’m a block or so away from home.

1976 KZ 900 A4 kzrider.com/forum/11-projects/613548-1976-kz-900-a4
1976 KZ 900 B1 LTD
1978 KZ 1000 B2 LTD
1980 KZ 750 E1
Kowledge Speaks, But Wisdom Listens.
Jimi Hendrix.

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30 Jul 2022 05:58 #871304 by DOHC
Replied by DOHC on topic Leaky Carburetors
I had the same problem with my kz1000.  Fuel would weep from the #1 carb at the top of the bowl and drip on the starter and chain cover.  After a while the carb and covers would be stained with brown varnish.  No fuel came out of the overflow, so I don't think it was a float valve issue.  Early on I replaced the bowl gaskets but that didn't fix it.

During a recent refresh I rebuilt the carbs completely, so I can't really say that any one thing fixed this issue for me, but with this problem in mind a bought the extra thick gaskets from Z1 Enterprises.  So far no leaking bowls, and no fuel stains.

www.z1enterprises.com/gasket-float-bowl-...slide-1976-1978.html

 

'78 Z1-R in blue , '78 Z1-R in black, '78 Z1-R in pieces
My dad's '74 Z1
'00 ZRX1100

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30 Jul 2022 07:05 #871308 by Nessism

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