Carb spitting gas - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 4 (permalink) Old 06-01-2012, 12:22 PM Thread Starter
2FAS4U
 
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Carb spitting gas

1986 that sat for 2 years, ran good before hand, just a little lean.
Ear shave by previous owner.
project bike for my step son.
We cleaned the carbs, which weren't too bad and installed 142 mains and 42 pilots.
The left side carb spits some gas out of it when running, but does not leak gas when sitting.
It starts better if he holds up on the metal piece that moves up and down with the diaphragm.
I'm much better with car carbs.
Float too high? Float needle valve sticking?
What effect does shimming the needle valve have?
Thanks

Last edited by 2fas4u; 06-01-2012 at 12:27 PM.
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post #2 of 4 (permalink) Old 06-01-2012, 12:34 PM
Crap, I WAS in 5th gear.
 
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Originally Posted by 2fas4u View Post
1986 that sat for 2 years, ran good before hand, just a little lean.
Ear shave by previous owner.
project bike for my step son.
We cleaned the carbs, which weren't too bad and installed 142 mains and 42 pilots.
The left side carb spits some gas out of it when running, but does not leak gas when sitting.
It starts better if he holds up on the metal piece that moves up and down with the diaphragm.
I'm much better with car carbs.
Float too high? Float needle valve sticking?
What effect does shimming the needle valve have?
Thanks
Sounds like a stuck float needle- the petcock shuts off fuel when vacuum is not applied from the carb venturi. Shimming the needle will richen your mixture a little earlier, and is done to cure a cruise (1/4 throttle) hesitation, or to fix a slightly lean condition from 1/4 to 3/4 throttle.
http://www.gadgetjq.com/keihin_carb.htm
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post #3 of 4 (permalink) Old 06-01-2012, 01:26 PM Thread Starter
2FAS4U
 
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Awesome link. Thanks
Guess the carbs are coming back off?
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post #4 of 4 (permalink) Old 06-01-2012, 06:59 PM
Crap, I WAS in 5th gear.
 
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Quote:
Originally Posted by 2fas4u View Post
Awesome link. Thanks
Guess the carbs are coming back off?
Join the club. I had mine off three times when I cleaned them. Ultimately had to upsize my pilot and shim the needle. My intake and exhaust are stock. I assume that some component(s) wore to the point that my mixture requirement changed a tad. I had some hesitation at 1/4 throttle cruise and couldn't decide whether to mess with the mains needles or pilot, so I did both with great results. I did't replace my float needles, which may have affected float height a bit, but I checked the float levels before removing the carbs the third time, at they were fine. I may have been able to fix my problem by increasing the float heights a little, but pilots and needle shims were easier.
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