Tuning (Jetting) Keihin CV Carbs for the VN750 - Page 3 - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Carbs and Fuel System
From the gas tank to the carbs
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post #21 of 54 (permalink) Old 09-22-2017, 09:43 AM
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I'm running with the stock exhaust. Earshave and jetting are the only mods so far. I contacted an old friend of mine who is also a certified Kawasaki tech/mechanic. His opinion is that I should re-install the stock air box or I will be fighting this issue for a long time. His experience is that with the pods installed that there is not enough velocity to properly lift the slides and that is why I'm not getting any power!
Other opinions?
Thanks,
Steve
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post #22 of 54 (permalink) Old 09-22-2017, 12:57 PM
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Hundreds, probably thousands, of earshaved Vulcans are shaking their heads.

My first thought was a dirty pilot jet/idle circuit, but I need to read more and I'm out of time right now, will check more later.

If a slide isn't lifting, it can easily be a cracked diaphragm or the dia. isn't seated properly at the top cover. Do the woosh test. - remove pod, lift slide to the top and release it, listen for a steady woosh sound and note there should be some resistance as the slide drops. If it snaps back down with gravity, or one side has a different sound, the diaphragms need checked, re-seated, or replaced. Don't mix slide needles, they're different on each carb.

I'm earshaved on stock exhaust with stock jets and slide settings.

Make sure the carb bowl vent is sheltered from wind. Wind on the vent will cause bogging. Where do you have your vent? Placement is critical.

edit: I now see this is an older thread and there was just a couple of posts to catch up on. gotta go...

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Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
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Owner's Manual: http://www.mediafire.com/file/nscb5f...ers+Manual.pdf

Last edited by Spockster; 09-22-2017 at 01:02 PM.
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post #23 of 54 (permalink) Old 09-22-2017, 04:58 PM
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142/40 is what you'd run with a free flowing exhaust AND an earshave. many have gotten away with stock jetting with just an ear shave,but each bike is different. my bet is you're bike is running too rich

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post #24 of 54 (permalink) Old 09-22-2017, 07:20 PM
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oh,and how about an introduction in the newbie section?

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lowered with progessive 412 10" shocks
rejetted for K/N Pods part#rc 2340
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post #25 of 54 (permalink) Old 09-22-2017, 09:15 PM
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I checked the slides and they are properly seated and swooshing properly when lifted and released. i installed the 142 /40 main and slow jet per suggestion. i don't smell gas in the exhaust even when revving it up on my lift. i did the needle shim also using 2 shims per. If anything, it seems very lean to me. It starts up very easily and idles perfectly at 1k but the idle does not change at all even when I screw the idle adjusting screw all the way in or 5 turns out (both carbs of course). I temporarily taped up the K and N pods with masking tape leaving only about 3/4" open at the small end of the pods to restrict the air intake but it didn't seem to change the performance much. Still had no power and could only get it to 70 mph.
Gonna go back to stock jetting and remove the shims tomorrow and see what happens. Thanks for all the replies so far.
How do I get to the newbie section for an intro?
Thanks,
Steve
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post #26 of 54 (permalink) Old 09-22-2017, 09:28 PM
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it's in the vn750.com news section,under newbie check in

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lowered with progessive 412 10" shocks
rejetted for K/N Pods part#rc 2340
sportster seat

'I didn't lose my mind.i gave it away

BRING BACK WOLFIE."Peace and Carrots"RIP
"And I'm free...as a bird"John Lennon Free as a Bird
"I only carry when I have my pants on"Joe Robinson RIP aka Old Dog
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post #27 of 54 (permalink) Old 09-22-2017, 09:54 PM
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Originally Posted by sbmisajw View Post
I checked the slides and they are properly seated and swooshing properly when lifted and released. i installed the 142 /40 main and slow jet per suggestion. i don't smell gas in the exhaust even when revving it up on my lift. i did the needle shim also using 2 shims per. If anything, it seems very lean to me. It starts up very easily and idles perfectly at 1k but the idle does not change at all even when I screw the idle adjusting screw all the way in or 5 turns out (both carbs of course). I temporarily taped up the K and N pods with masking tape leaving only about 3/4" open at the small end of the pods to restrict the air intake but it didn't seem to change the performance much. Still had no power and could only get it to 70 mph.
Gonna go back to stock jetting and remove the shims tomorrow and see what happens. Thanks for all the replies so far.
How do I get to the newbie section for an intro?
Thanks,
Steve
Sounds like you might be trying use the air adjustment screws to set the idle speed. There's one on the side of each carb, usually set around 2 to 2.5 turns out.

The idle adjustment is a single black knob on the left side that sets the idle on both carbs.

2003-21k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Repair Manual: http://www.mediafire.com/file/mj7z81..._Catalogue.pdf

Owner's Manual: http://www.mediafire.com/file/nscb5f...ers+Manual.pdf
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post #28 of 54 (permalink) Old 09-23-2017, 11:18 AM
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Sprockster

Thanks for the reply. I hear you. I'm aware of the difference between the idle speed adjuster and the 2 air/idle screws. I set the the 2 air/idle screws out 2 1/2 turns to begin with and it idled perfect at about 1k but it doesn't change when I mess with the 2 air/idle screws which I find really baffling.
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post #29 of 54 (permalink) Old 09-23-2017, 12:02 PM
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Sprockster

Thanks for the reply. I hear you. I'm aware of the difference between the idle speed adjuster and the 2 air/idle screws. I set the the 2 air/idle screws out 2 1/2 turns to begin with and it idled perfect at about 1k but it doesn't change when I mess with the 2 air/idle screws which I find really baffling.
Steve
I thought so after I saw your intro post. You don't do that much wrenching and not know the differences.

When a mixture screw doesn't respond to adjustment, that sometimes means the idle is set above the point where that circuit takes effect. The idle rpm could be right where it belongs, but the setting required has the carb slide/butterfly set above the point of the idle circuit. One trick with automotive carbs is to bring the idle below normal, then do the mixture adjust for highest rpm or highest vacuum.

Or, it can mean the circuit is clogged, so the screw has no effect.

An air leak on a boot can also affect adjustment ... Does your rpm hang any after a rev, slow to come back down?

Do your plugs show a lean color, or rich?

2003-21k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Repair Manual: http://www.mediafire.com/file/mj7z81..._Catalogue.pdf

Owner's Manual: http://www.mediafire.com/file/nscb5f...ers+Manual.pdf
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post #30 of 54 (permalink) Old 09-25-2017, 02:34 PM
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You don't need to re-jet with the ear shave

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