How to pick jet sizes without being a total knucklehead - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 7 (permalink) Old 02-06-2016, 06:12 PM Thread Starter
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How to pick jet sizes without being a total knucklehead

I've had a lot of requests on various forums to finish my jet size chart so it auto-calculates, so here it is. Let me know if there are any errors.

Mods might want to pin/sticky this.

Just plug in your reference sizes, and try to be realistic (conservative) with the power gains you expect to have. I think the last bike I had entered was a VN1500 (US version), so put in stock sizes for your bike. Should be #38/#132.

https://drive.google.com/file/d/0B0D...ew?usp=sharing
Attached Files
File Type: zip Hex's Keihin Jet Size Universal Calculations.zip (28.6 KB, 122 views)

Last edited by Hexadecimus; 02-06-2016 at 06:15 PM.
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post #2 of 7 (permalink) Old 02-06-2016, 06:40 PM Thread Starter
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It gets more complicated because the pilot system also pulls fuel in most CV carbs, you usually have to jump up 10-15% on the pilot and dial the pilot screw back to compensate, or keep it stock and open the screw way up, balance with the mains, consider that the pilot is adding close to 2% difference on some carbs, some have an intermediate circuit, accelerator pump, etc... but this is a good place to start.

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post #3 of 7 (permalink) Old 02-06-2016, 09:17 PM
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OK Hex I will stick it even though I doubt that I will ever have need for the info personally.

Gordon

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TOP TEN THINGS A NEW RIDER/OWNER SHOULD DO. Click on link.
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post #4 of 7 (permalink) Old 02-06-2016, 09:29 PM
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Sweet Hex.thanks

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post #5 of 7 (permalink) Old 02-09-2016, 12:04 PM
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Hey Hex,

I can't open the second link which is a zip file: It tells me it is corrupted.

I took a look at the first link which is a chart, and I have to be honest here...I am not sure what I am looking at.
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post #6 of 7 (permalink) Old 02-10-2016, 01:22 PM Thread Starter
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Thanks for letting me know. I'll check the zip when I get off the road. Long road trip.

You just punch your current jets into the top as a reference point. It calculates the two charts automatically.

It has labeled columns for each jet. It shows a list of sizes, area of the jet port for each size, and the % difference in fuel, which you choose based on how much more air/power your mods are making. I could have left it as one chart, but two means you can see both jets at the same time.
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post #7 of 7 (permalink) Old 02-10-2016, 01:44 PM
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East bound and down loaded up and truckin. We're gonna do what they said can't be done.we've got a long way to go and a short time to get there.I'm east bound,just watch ole Bandit run

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1986/5 Vn700/750 Frankenfook cross eyed bitch "Mellisa Fayhe"
I am a BIKER and i'm proud.FREEBIRDS MC CENTRAL NY

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

Last edited by OleDirtyDoc; 02-10-2016 at 02:01 PM.
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