Zr7s 03 Carbs big problem Help please

862 Views 13 Replies 5 Participants Last post by Zed7, 3 mo ago

Diablo SS

Discussion Starter · 3 mo ago

Hi everyone
I have a problem with carburetors from kawasaki zr7s 2003 keihin cvk 32
The needle bore is polished
new needles
carburetors are constantly overflowing
however when the level is adjusted it still overflows at the two holes on the side of the air filter
My question is if anyone has the same carburetors and can they check and take pictures of this part
It seems to me that it should be closed with a ball
They are constantly overflowing, so it seems to me that gasoline is passing through there
thank you
sorry for bad english

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Zed7

· #2 · 3 mo ago

Welcome.
If it is closed with a ball on one then it should be closed with a ball on all of them. If I’m seeing the picture right. I’d plug it.
But is that hole above the fuel level once the floats shut off the fuel?
Your floats are adjusted and assembled correctly?

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Diablo SS

Discussion Starter · #3 · 3 mo ago

Its open on all four, you can se a brass inside when you look...I think it must be under but i try so many adjust of float, its not my first time to cleaning and adjusting carbs but this one is eating me, its overflow with new needels, the seats is polished and like new, i try to fully raise down and fully raise up its doing same, but when you check to close with fingers its closing good, only when you atach the hose and prime its start to overflow, its killing me, i use service manual and inspect everything to many times butt it wont stop owerflow...

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Hugo Delgadillo

· #4 · 3 mo ago

.......Have a ZR-7 carb rack set sitting in my garage. Those holes do not have balls or any plug. That is the starting jet passage. I have bench tested these carb rack in a bench and if needles are proper size, and level is just slightly about the seam, they do not leak when filled by fuel.

If you are sure the needles are proper size, (many needles look same but they are not, ....specially aftermarket), .....then I'd drop the level some. Use the wet U-tube method to check where the level is. Don't rely solely on the dry float height method.

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Diablo SS

Discussion Starter · #5 · 3 mo ago

Needles is same like old ones, size and everything, even i check on internet for right size and they are ok. I send it to man who is pro with carbs, he tell my that probably problem with floats after some time they become havier, how who noes, but meny times he hawe problem with that, i wait now when he check and posting here what is the problem...

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Zed7

· #6 · 3 mo ago (Edited)

I believe, while bench testing, you can attach a hose to the carb inlet and use a Mity Vac on hose with the carbs upside down to see if the valves are sealing.
If the seats and needles are good then the only answer is float height. Either maladjusted or they are too heavy because of leak. There’s no other way for gas to get into the carbs except through those inlet valves.
Is the main fuel hose from the tank connected to the proper tee fitting on the carbs? I know that sounds like an insulting question but it is not meant to be.

Also, those rubber tubes are vent tubes and they are meant to be mounted above the carburetors. There’s grooves or clips for them.

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Hugo Delgadillo

· #7 · 3 mo ago

...never heard of floats becoming heavier....It they did, it could only happen by build up, which would be rather insignificant. Even if real, which I doubt, you could simply drop the level to compensate.

My question;.................... do you really know where the level is????

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Diablo SS

Discussion Starter · #8 · 3 mo ago

Yes for sure, its not first time to adjusting it, i use service manual, i make a degree like is on service manual and make it on 17mm but its overflow even if i put it all the way down to close it when little gas come in but it owerflov, and when i try to close it with fingers like stimulate the presure on floats and make presure on hose with mouth it close it good no leaking air, even if i make vacum it stay...But when i put it on gas its starting to overflow...

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Zed7

· #9 · 3 mo ago

Diablo SS said:
Yes for sure, its not first time to adjusting it, i use service manual, i make a degree like is on service manual and make it on 17mm but its overflow even if i put it all the way down to close it when little gas come in but it owerflov, and when i try to close it with fingers like stimulate the presure on floats and make presure on hose with mouth it close it good no leaking air, even if i make vacum it stay...But when i put it on gas its starting to overflow...

Yeah, gas seems to get through everything. Maybe the floats are somehow binding up in their mounts after assembly?

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Hugo Delgadillo

· #10 · 3 mo ago (Edited)

DELETE

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Obo

· #11 · 3 mo ago

There could be a few things at play here.

You may have a float that is not shutting the fuel off when the bowl is full which is what is causing the overflow. It could be a bad rubber tip on the float needle of a bad float. As for them getting "heavy" I've seen them get a hole and fill with gas, so they sink and keep the needle open.

It's also possible (but unlikely) that the brass insert in the carb where the float bowl needle sits is damaged. If it is damaged there's no real repair for that. I've only seen that once on here and is very very uncommon.

Next would be does this happen with the bike is running or off? If the bike is off, and the fuel petcock is not on PRIME then you also have a petcock issue. The petcock is vacuum operated and should not pass gas unless the bike is running or it's in the PRIME position.

If you had an overflow issue and filled the airbox with gas you may also have gas in the engine oil case as well as the airbox oil drain bottle located behind the right foot peg mount.

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clone5

· #12 · 3 mo ago

Hugo Delgadillo said:
...never heard of floats becoming heavier....It they did, it could only happen by build up, which would be rather insignificant. Even if real, which I doubt, you could simply drop the level to compensate.

My question;.................... do you really know where the level is????

If floats no longer float due to plastic degradation they can fill with fuel and become "heavier"

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clone5

· #13 · 3 mo ago

Overflowing carbs mean that the fuel is not being shut off
This is mainly because of the float valves not seating correctly due to age, wear or debris. Or all of the above
Grab yourself a new set of float valves and ensure the seats are clean and smooth prior to install.

Google "zr7 float valves" to see the part I'm referring to

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Zed7

· #14 · 3 mo ago

clone5 said:
If floats no longer float due to plastic degradation they can fill with fuel and become "heavier"

You would actually see the gas inside the float upon removal if they were compromised somehow, which I doubt. But I think despite his new float needles, they just aren’t sealing well. It doesn’t take much. Just a little crap on the surface of the valve seat will do it. That and a leaky petcock.

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