Vacuum Issues - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 33 (permalink) Old 09-16-2006, 05:56 PM Thread Starter
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Vacuum Issues

Hello again, you may remember me with the fuel problem....

https://www.vn750.com/forum/showthread.php?t=2325

To continue the quest for a better performing bike, I need to know what others have experienced with their vacuum guage.

Mine will wildly swing at idle but will smooth out as throttle is increased.

I syncronized the carbs today and they will sync at 4000 rpm but at idle the rear cylinder has a lot higher vacuum than the front.

I am using Marty's yard stick manometer

http://www.powerchutes.com/manometer.asp

any sugestions? I know from a vacuum check on my car, that the needle should be steady at idle, otherwise you have a vacuum leak or the carbs are too rich or too lean. Which is it for these bikes? Do I need to enrichen the jets? (Oh yeah, I forgot to tell you I only have one vacuum line from the front carb, all the others are gone, and I replaced that hose so probably not a leak.....will the idle adjust effect the sync?

The bike seems to run ..OK, not super, but ok. Maybe I am too pickey and expect this 2 cylinder to run like my '71 honda 750 4cyl.

Thanks for any assistance you can provide.

I will be ear shaving in the very near future and need access to a set of jets and shims, I have tried the links in the verses, but none acctually tell me which jets and shimms are for the VN750.....

Thanks again.
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post #2 of 33 (permalink) Old 09-17-2006, 10:56 AM Thread Starter
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I guess everyone elses' vacuum is fine....
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post #3 of 33 (permalink) Old 09-17-2006, 12:14 PM
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I have never checked mine so i cant help

Chad Falstad "Hawk"
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post #4 of 33 (permalink) Old 09-17-2006, 12:22 PM
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Quote:
Originally Posted by Ccspinner
I have never checked mine so i cant help
Ditto


AKA: Tim & 'The Adventure Cycle' VROC #24567, NEVROC, SteelCity VROC


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post #5 of 33 (permalink) Old 09-17-2006, 09:08 PM Thread Starter
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Maybe I will have to repost during the week....

Thanks
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post #6 of 33 (permalink) Old 09-17-2006, 09:22 PM
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Me either. Although some people say that the vaccum between my ears is good. I don't know how they know my bike has ears...

2000 A16
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post #7 of 33 (permalink) Old 09-18-2006, 10:12 AM
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When the bike is at idle "I think 1100 RPM" you will need to restrict the tube to get a steady reading. Most carb sync. tools come with little wire restricters. If yours doesn't you will need to find a way to pinch off the tube a bit. Sometimes a small pair of loccking pliers or small c-clamps. Hope this helps!
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post #8 of 33 (permalink) Old 09-18-2006, 09:14 PM Thread Starter
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tinocker, can you please explain in as much detail as you can, I cannot find any info on this. I can see restriction, but I cannot see how it will help with on side having more vacuum than the other at idle....There needs to be some way to adjust each side????

Thanks.

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post #9 of 33 (permalink) Old 09-30-2006, 07:31 PM
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I'm having the same rpm swing at idle - dta116, did you ever find a solution to your problem with the same?
Thanks.

C
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post #10 of 33 (permalink) Old 10-01-2006, 03:08 AM
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Quote:
Originally Posted by dta116
There needs to be some way to adjust each side????
If you need to set the carbs so one matches (or is in-sync with) the other, I don't see why you'd need to be able to adjust both.
Just adjust the one 'til it is the same (or very nearly the same) as the other.
Or am I missing something else here?
All I could find on a search were instrucions which say "Adjust the dampening valve to reduce the studder of the needle, or mercury"
There were no pictures to go along with it.


AKA: Tim & 'The Adventure Cycle' VROC #24567, NEVROC, SteelCity VROC


"When life throws you curves,
Aim for the apex."

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