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Carb leak flow related to vacuum line?
- gte105u
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1981 KZ550 A2
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- Patton
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I bought a bike last weekend and have been working on it some (see my other noob related threads). I was told that there was a small carb leak. I just added some Sea Foam to hopefully take care of the issue. So here's my question. When I was poking around under the tank I saw the vacuum line was disconnected at the fuel tap. I reconnected it, and now the carb leak seems to be at a higher flow. Is this possible? Am I just noticing it more, or should I re-disconnect the vacuum line until the carb leak is fixed?
Vac line should remain connected to petcock. If not connected, the vac line should be plugged, or capped at the carb nipple.
Is the carb leakage issue while the engine is running?
When engine isn't running, carb leakage likely not influenced by whether or not vac line is connected to petcock.
Initial guess would be leaking float valve(s), and perhaps petcock not performing up to snuff.
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1973 Z1
KZ900 LTD
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- gte105u
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1981 KZ550 A2
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- Patton
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Here's an example (see below).
In this example, the vac to petcock is on #2 carb.
Sometimes the vac to petcock is on #3 carb.
Other carbs don't have a separate dedicated vac to petcock nipple, and just use one of the vac sync nipples to supply vacuum to a vacuum petcock.
Unless used to supply vacuum to a vacuum petcock, or used incident to a "clean air" hose system, a vac nipple should be plugged during normal operation.
In other words, an unused vac nipple should be plugged during normal operation.
An open unplugged vac nipple will create a huge air leak.
Good Fortune!
[Click on image to enhance view.]
1973 Z1
KZ900 LTD
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- gte105u
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1981 KZ550 A2
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- Patton
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Thanks for the heads up. Is the vacuum line coming from the between carbs 1 and 2 or 3 and 4? There is only one line under the tank besides the fuel line, and it is coming from near carb 4. Is the vacuum line towards the front or back of the vent?
The earlier posted pic is a view when looking at the carbs from the rear where the air enters.
Those carbs have vac nipple between 1st and 2nd carbs where the tube attaches that runs from there to the petcock.
As noted, some carbs have such vac nipple between 3rd and 4th carbs.
While other carbs have no such dedicated vac nipple at all.
When carbs do have the vac nipple between 1st and 2nd or between 3rd and 4th, it's easy to confuse such vac nipple with either of the two VENT nipples. As shown, one vent nipple is between carbs # and #2. And the other vent nipple is between carbs #3 and #4.
The two vent nipples run though their attached tubes to open air, often underneath the seat or underneath the bike.
Here's a pic showing one of the two vent hoses (see below).
Good Fortune!
[Click on image to enhance view.]
1973 Z1
KZ900 LTD
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1973 Z1
KZ900 LTD
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- gte105u
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Anyway, after digging through the Kawasaki parts diagrams, I think I know what I am looking for. It looks like there are two vent nipples feeding from one location between carbs 3 and for. Does it matter where they run to? The vents are behind (towards the back of the bike) the vac line, also between carbs 3 and 4. Please take a look at the pics below and advise if I am missing anything here. Thanks again
1981 KZ550 A2
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- Motor Head
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- FIX UP YOUR BIKE RIGHT AND CHEAP
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1982 KZ1000LTD K2 Vance & Hines 4-1 ACCEL COILS Added Vetter fairing & Bags. FOX Racing rear Shocks, Braced Swing-arm, Fork Brace, Progressive Fork Springs RT Gold Emulators, APE Valve Springs, 1166 Big Bore kit, RS34's, GPZ cams.
1980 KZ550LTD C1 Stock SOLD Miss it
1979 MAZDA RX7 in the works, 13B...
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- gte105u
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1981 KZ550 A2
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- Motor Head
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- FIX UP YOUR BIKE RIGHT AND CHEAP
- Posts: 5138
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1982 KZ1000LTD K2 Vance & Hines 4-1 ACCEL COILS Added Vetter fairing & Bags. FOX Racing rear Shocks, Braced Swing-arm, Fork Brace, Progressive Fork Springs RT Gold Emulators, APE Valve Springs, 1166 Big Bore kit, RS34's, GPZ cams.
1980 KZ550LTD C1 Stock SOLD Miss it
1979 MAZDA RX7 in the works, 13B...
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- gte105u
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1981 KZ550 A2
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