does my carbs needs to be tuned? - Page 4 - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Carbs and Fuel System
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post #31 of 42 (permalink) Old 11-06-2017, 08:59 AM Thread Starter
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that sound good, thanks for the input also the front exhaust is popping on idle, no constantly but you can hear it, maybe 1 or 2 times every 5 seconds. its well adjust i believe both exhaust have almost same temp back its a 2.5 turn front at 3 turns, if i put front on 2.5 turns it runs colder that you may touch the pipe with temp gloves of course, which means lean, back is untouchable

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post #32 of 42 (permalink) Old 11-06-2017, 10:24 AM
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Well, a lean condition causes combustion temp to rise. Rich will make it cooler.
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post #33 of 42 (permalink) Old 11-06-2017, 11:31 AM Thread Starter
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Well, a lean condition causes combustion temp to rise. Rich will make it cooler.
you are right, but i give it a bit more fue and got better and hotter, any idea why? and what size of shims should i use or how many?

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post #34 of 42 (permalink) Old 11-06-2017, 11:39 AM
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Could be it was so lean, no combustion or very little was able to occur, so adding fuel lit the fuse. Of course shorter pipes will be hotter just because of less surface for heat transfer.

I would start with one shim and go from that. Size, I'm not sure, but there's some info around here on that. The shim allows the slide needle to be higher, letting more fuel in, at a given throttle opening.
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post #35 of 42 (permalink) Old 11-06-2017, 12:31 PM Thread Starter
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sounds good, will order a shim pack and start there i just i don't have to putt out the carbs again (5 times already) to install this

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post #36 of 42 (permalink) Old 11-06-2017, 01:12 PM
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The slide needle can make big changes in the fuel ratio. Some needles have multiple grooves so you can just move a clip into another groove, but on the VN we have to use shims.

On my 2-stroke, one notch on the slide needle takes it from burbling rich, to screaming wheelies at 10k rpm.

I haven't had to rejet my VN carbs or change anything except to get the dirt out. Stock pipes though. It might take some trial and error to get the shims right, but it's better than being too rich and not knowing it, that can lead to bad carbon buildup.

Keep an eye on the spark plug color, just pull the plugs that have no deep well, no need to check both on the same cylinder.

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post #37 of 42 (permalink) Old 11-07-2017, 09:33 AM Thread Starter
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took the spark plugs out and they have that brownish color, like cooper color on both cylinders. i think they are burning right. just dont know why i'm getting that hesitation at light throttle around 4-4.5K rpm

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post #38 of 42 (permalink) Old 11-07-2017, 11:28 AM
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Quote:
Originally Posted by eltiti21 View Post
took the spark plugs out and they have that brownish color, like cooper color on both cylinders. i think they are burning right. just dont know why i'm getting that hesitation at light throttle around 4-4.5K rpm
Could be the transition between pilot + main is a bit lean, the slide needle should help with that.
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post #39 of 42 (permalink) Old 11-07-2017, 12:22 PM Thread Starter
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Could be the transition between pilot + main is a bit lean, the slide needle should help with that.
okie, i will turn it out a bit more see if it helps, thanks for your comments and knowledge, i highly appreciate it.

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post #40 of 42 (permalink) Old 11-07-2017, 01:27 PM
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okie, i will turn it out a bit more see if it helps, thanks for your comments and knowledge, i highly appreciate it.
You're welcome, happy to help.

Not the air screws, the shim under the slide needles.

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__________________________________________________ ____________
Repair Manual: http://www.mediafire.com/file/mj7z81..._Catalogue.pdf

Owner's Manual: http://www.mediafire.com/file/nscb5f...ers+Manual.pdf

Last edited by Spockster; 11-07-2017 at 01:29 PM.
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