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Carbs help please

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DonB
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Carbs help please

#1 PostAuthor: DonB » Tue Jun 25, 2019 4:10 pm

Z9 A4

Carbs keep leaking out of the Overflow pipes and occasionally out of the back of the carbs.
I've tried float heights, float valves and nothing will stop it. Stops for an hour or so but then starts again.
Can anyone guide me in the right direction please?

kev edwards
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Re: Carbs help please

#2 PostAuthor: kev edwards » Tue Jun 25, 2019 4:28 pm

Has to be float valves letting by.

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Pigford
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Re: Carbs help please

#3 PostAuthor: Pigford » Tue Jun 25, 2019 5:19 pm

If out brass overflow - they can split internally!
And on the 7th day... Zeds were created!

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Gonzo
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Re: Carbs help please

#4 PostAuthor: Gonzo » Tue Jun 25, 2019 11:29 pm

Petcock not shutting fuel off?
1978 Z1000A2
Previous Zeds:
1975 Z1B
1982 Z650F3

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Ultim8pc
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Re: Carbs help please

#5 PostAuthor: Ultim8pc » Wed Jun 26, 2019 8:37 am

Have you done the following:
Replaced the float valves, seats and washer?m (Even when slightly worn they can leak).
Checked the actual fuel height, not just measured the float height? (Often the actual fuel height can be incorrect even though you've set the float height correctly).
Fitted an inline fuel filter? (To prevent crap finding it's way into the carb and jamming the fuel valve).
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DonB
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Re: Carbs help please

#6 PostAuthor: DonB » Wed Jun 26, 2019 8:14 pm

Thank you everyone, I will carry on and check w eh by what you have suggested

weaver
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Re: Carbs help please

#7 PostAuthor: weaver » Thu Jun 27, 2019 7:45 pm

first thing to check is is fuel tap passing if it is sort that first and it will probably sort the problem.

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Re: Carbs help please

#8 PostAuthor: needaz1100r » Fri Jun 28, 2019 6:36 am

weaver wrote:first thing to check is is fuel tap passing if it is sort that first and it will probably sort the problem.


The carbs shouldn't overflow because the fuel tap lets petrol through. It will let you mask the problem though.
Cheers,

Mark.

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Ultim8pc
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Re: Carbs help please

#9 PostAuthor: Ultim8pc » Fri Jun 28, 2019 10:53 am

needaz1100r wrote:The carbs shouldn't overflow because the fuel tap lets petrol through. It will let you mask the problem though.

I agree. Would only overflow if the fuel height is too high, the the float valve is leaking, or a float is suck.
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http://www.quick-glo.co.uk
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Re: Carbs help please

#10 PostAuthor: weaver » Sun Jun 30, 2019 4:36 pm

needaz1100r wrote:
weaver wrote:first thing to check is is fuel tap passing if it is sort that first and it will probably sort the problem.


The carbs shouldn't overflow because the fuel tap lets petrol through. It will let you mask the problem though.


true but if you fix the fuel tap you will never have a problem with carbs over filling again if its your float valves that are passing.

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Re: Carbs help please

#11 PostAuthor: needaz1100r » Mon Jul 01, 2019 6:37 am

weaver wrote:
needaz1100r wrote:
weaver wrote:first thing to check is is fuel tap passing if it is sort that first and it will probably sort the problem.


The carbs shouldn't overflow because the fuel tap lets petrol through. It will let you mask the problem though.


true but if you fix the fuel tap you will never have a problem with carbs over filling again if its your float valves that are passing.


That's only true while the fuel tap is off and presumably the engine not running, if your float valves are passing they can't maintain the correct fuel level when the tap is on, how do you know the level is correct when the bike is running? It might not come out onto the floor, but could be drawn into the engine causing rich running, or at least poor fuel consumption.
Cheers,



Mark.

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Re: Carbs help please

#12 PostAuthor: weaver » Mon Jul 01, 2019 7:57 am

the op has tried everything inside the carbs to no avail,if the tap is vacuum operated and is passing with the engine off the head of fuel will push petrol past the float valves,sort this and job done.


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