Author Topic: tuning and jetting  (Read 722 times)

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Offline batboy

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Re: tuning and jetting
« Reply #25 on: August 20, 2019, 05:50:46 pm »
Shimming the needle worked, maybe too well. Part throttles are plenty rich usually in the 12s AFR. Idle is mid to high 13s. I only did one short WOT and that started out in the 12s and richened up in the high 11s at 8k rpm when I let up. So, the 125 main jet was not too small after all. Oddly enough, I have the same 125 main jets and 35 pilot jets in my 32mm carb rack (OEM ZG1000). The cool thing is there is no flat spots or bogging anywhere I could tell throughout the rpm  range at part throttle.

Here is what I also learned. Not sure it the ZG1000 is like this, I thought all the needles were the same. But, I looked at the numbers on the needles in the 36mm carbs and there are two different part numbers: N36D in carbs 1 & 4 (outer) and N36E in carbs 2 & 3 (inner). I looked on a parts website with exploded diagram and it shows up there too on the ZX1000A list. One part number must be leaner than the other. But, which is which? The needles looked a little banged up. I might buy new ones if I knew which part number flows better.

What to do? The shims are 0.5mm thick. Are there thinner shims? Think I need to remove the needle shims or find some that are only half as thick. Also, I need to figure out what the difference is on the needle part numbers. Guess I should check to see if those needle are even available.

Unrelated to tuning, I finally got my Soupy adjustable lowering links to play nice with my ZZR1200 rear shock.

1988 Kawasaki Concours ZG1000 - Ninja Edition
Bike has the usual accessories and modifications

Offline m in sc

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Re: tuning and jetting
« Reply #26 on: August 20, 2019, 06:06:17 pm »
if you have a hole punch kit (a real one) you can make shims out of shim stock any thickness you want. Also try turning the fuel screws IN 1/4 turn. or buy actual needle shims in varying sizes.

 http://www.wahlracing.com/Needle-Shim-Kit.html


Offline MAN OF BLUES

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Re: tuning and jetting
« Reply #27 on: August 20, 2019, 08:14:08 pm »
THE "E" needles are the "inner" ones, the "D" ones are the outers...
Inners run leaner, and you may find the actual jet sizes are smaller on some bikes.. not all, but some...
https://www.kawasakimotorcycle.org/forum/vintage-motorcyle-info/101237-86-zx1000r-a1-keihin-cvk-36-question.html

I used the Dyna ones, with "slots" and  "E" shaped clips, which allow up/down locations/adjustments... the fixed position like you have, are segregated by D/E to accomplish this. Hope this helps.

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Offline batboy

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Re: tuning and jetting
« Reply #28 on: August 20, 2019, 08:48:17 pm »
Ok, the inner N36E is the leaner of the two. That's what I was trying to figure out.

The throttle started binding up and I think the sync is messed up again. I had static bench synchronized these carbs before I put them on the first time. Yesterday afternoon I spent a long time redoing the bench sync and now it's way out of whack again. Either I'm doing something wrong or there are loose or worn parts. I'm done for the day, we have another heat advisory.

Top priority, figure out why the carbs won't stay in sync and decide which needles to use.

[UPDATE: feels like there's extra play in the butterfly of carb #1. It's definitely out of sync again.]
« Last Edit: August 20, 2019, 08:56:51 pm by batboy »
1988 Kawasaki Concours ZG1000 - Ninja Edition
Bike has the usual accessories and modifications

Offline Steve in Sunny Fla

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Re: tuning and jetting
« Reply #29 on: August 20, 2019, 09:16:13 pm »
 ahhh, from a guy who now tunes on a Laptop and doesn't get dirt under his nails anymore, I can tell you I don't miss the "old days"  :nananana: :nananana: :nananana:  :rotflmao: :motonoises: :motonoises: ;)  Steve
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Offline MAN OF BLUES

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Re: tuning and jetting
« Reply #30 on: August 20, 2019, 11:44:26 pm »
ahhh, from a guy who now tunes on a Laptop and doesn't get dirt under his nails anymore, I can tell you I don't miss the "old days"  :nananana: :nananana: :nananana:  :rotflmao: :motonoises: :motonoises: ;)  Steve


we certainly don't "miss"them, but we remember every single thing.. and make a point of saying "Ya really don't wanna do...."  but it's all a good learning curve.. and one worth (i don't know why, but say yes.. worth) doing.. remaining a bit humble, and reflecting is what matters.. I hate seeing people slam a thumb with a hammer..
 :rotflmao: :great: :great: :great: :great: :great:

30 YEARS OF KAW.....Rich R. (the other one..)  COG 5977  JUSTAMEMBAHNOW
and if you are gonna call me names... it's MR. Analdweeb if you please...

Offline Lee

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Re: tuning and jetting
« Reply #31 on: August 21, 2019, 09:39:59 am »
Do not have a dog in this one. Do enjoy the read though.

Curious as well, What is the logic in leaning the hotter inner cylinders? Would seem jetting richer would be required to utilize cooling effect of fuel.

Seem to remember my v-twin is richer on rear cylinder for such reason. Am I missing or misunderstanding a technical point or theorem of some kind?

Offline batboy

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Re: tuning and jetting
« Reply #32 on: August 21, 2019, 11:15:17 am »
When the inner carbs are jetted different than the outer carbs, it's called staggered jetting (according to my google skills). Sometimes it's due to the head design and the flow characteristics. The outer two cylinders tend to run a little cooler, but I'm not sure what the logic is for running the outer richer unless it has something to due with air density. Staggered carb settings were more common back in the air cooled days.

I plan to go with all the same jetting (same needles too), because my wideband would read the AFR more accurately. With staggered jets, at best, you're seeing average AFR. I'm not sure I fully understand the logic either. Now on the ZG1000 32mm carbs, all the jets and needles are the same.

The real issue is that I'm having trouble finding new needles for the 36mm carbs. If I do find some, I hope to put the N36D needles in all four carbs without shims or use four shimmed N36E needles. I have N36H needles from a voyager (one is bent), but I have no idea if these are leaner or richer.
1988 Kawasaki Concours ZG1000 - Ninja Edition
Bike has the usual accessories and modifications

Offline batboy

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Re: tuning and jetting
« Reply #33 on: August 24, 2019, 06:35:07 pm »
Update: I have parts ordered. While waiting for them, I will probably need to pull the 36mm carbs back off to examine the throttle shafts. I can't keep the carbs in sync. The #1 carb  (left outer) seems like has a throttle shaft that is too loose (presumably worn out). I actually found a throttle shaft and butterfly for the left outer carb on eBay, so I bought it since it was cheap. But, I know it's more likely the bushing in the carb is worn, not the shaft. I want to repair this if possible.
1988 Kawasaki Concours ZG1000 - Ninja Edition
Bike has the usual accessories and modifications