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Discussion Starter · #1 ·
I have a restomod 1986 ZG1000 Concours with a hodgepodge of engine parts that is having fueling issues at high RPM. I sent the following in a tech support request to Dynojet who responded with a generic form letter and a .docx instruction on how to tape off the airbox inlet. I don't have an airbox as stated! Also if someone here has experience with aftermarket O2 ratio kit and fuel pump please note the brand and where to obtain.

Bike: 1986 Kawasaki ZG1000 Concours 2mm overbore using ZX11 pistons
Vance & Hines 4 degree advance ignition plate Stock ZG1000 igniter box, coils, wires, plugs
1984-86 GPz900 cams, stock advance GPz 34 mm carburetors with K&N pod filters
Ported head
Stock dual exhaust with slip on mufflers.

Question_Issue
Hello, hope you can help. I have purchased and installed the following: JET KIT FOR 1984 1986 KAWASAKI ZX900R NINJA SKU#2108
I have jetted several bikes with success in the past but this one is elusive with the parts available in the kit. I was able to get good low to mid range performance however it screams from 7 8k with this setting then hits a wall. Feels lean but I don t have a O2 sensor to confirm. I may need bigger mains and thicker needles. Slides are drilled and Dynojet springs installed #140 main jets Dynojet needles at highest slot
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1993 Zx-7 L Model, 2006 ZX-10R
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I have a restomod 1986 ZG1000 Concours with a hodgepodge of engine parts that is having fueling issues at high RPM. I sent the following in a tech support request to Dynojet who responded with a generic form letter and a .docx instruction on how to tape off the airbox inlet. I don't have an airbox as stated! Also if someone here has experience with aftermarket O2 ratio kit and fuel pump please note the brand and where to obtain.

Bike: 1986 Kawasaki ZG1000 Concours 2mm overbore using ZX11 pistons
Vance & Hines 4 degree advance ignition plate Stock ZG1000 igniter box, coils, wires, plugs
1984-86 GPz900 cams, stock advance GPz 34 mm carburetors with K&N pod filters
Ported head
Stock dual exhaust with slip on mufflers.

Question_Issue
Hello, hope you can help. I have purchased and installed the following: JET KIT FOR 1984 1986 KAWASAKI ZX900R NINJA SKU#2108
I have jetted several bikes with success in the past but this one is elusive with the parts available in the kit. I was able to get good low to mid range performance however it screams from 7 8k with this setting then hits a wall. Feels lean but I don t have a O2 sensor to confirm. I may need bigger mains and thicker needles. Slides are drilled and Dynojet springs installed #140 main jets Dynojet needles at highest slot
View attachment 22302
I would suspect either too much fuel or not enough fuel. If you back off the throttle a little bit, does it "regain" it's power or is it the same?
 

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Discussion Starter · #3 ·
I would suspect either too much fuel or not enough fuel. If you back off the throttle a little bit, does it "regain" it's power or is it the same?
Regains, although after one hard run it stalled coming to a stop. I'm tempted to try adding a fuel pump first but retrofitting on carbs with gravity float seats (larger diameter) can be iffy with fuel pressure overcoming the float.

I pitched this to jetsrus.com asking for jet and needle recommendations, the answer: sounds rich.🙄

If the pump doesn't help I'm buying a set of #144 jets. If that fails I'm getting a set of 1987 ZX1000B Keihin CVK36 carbs
 

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Discussion Starter · #6 ·
Have you done a plug reading?
I doubt changing the needle will do anything since it shouldn't play a part at WOT.
No, haven't done a throttle chop plug reading, I'll need a drag strip tune night to do that.
I haven't seen any black smoke or fouled any plugs. This engine is over 100cc larger than a GPZ900 so I'm guessing it's undercarbed even with Dynojet parts. I should have gone with the ZX1000B carbs to start with.
 

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Discussion Starter · #7 ·
I'm getting this to eliminate guessing. Since I have another project coming together, an overbored 1990 ZX10 street fighter, it'll come in handy for dialing that one in too.
 

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Dynojet carb kits SUCK......

Just my Carb Guru 2 cents. ;)

But @ 1st blush Id put 1 r 2 more shim(s) under the Jet Needle. 8 grand wall smacks of to lean, Needle just needs to come a red pubic hair more out of the MJ.
 

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W custom stuff it will require custom jetting. Try stepping up the main a few sizes and see where that gets u. To tune a carb from scratch u gotta get the idle right, then WOT, then experiment with needles/shims/slide hole to get the midrange and part throttle. And changing anything changes everything to some degree. But u r at the point of experimentation. Might see if u can look up the carb setups for a zx10, zx11, zrx12 (or zzr12) and draw up some ideas from what they run, both stock and modified. Good luck
 

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Are the dynojet springs softer or stronger then the oems the came with the carbs? My thoughts are the larger motor is creating more vacuum and drawing the slides up sooner which would cause a lean condition.
 

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Discussion Starter · #11 ·
Are the dynojet springs softer or stronger then the oems the came with the carbs? My thoughts are the larger motor is creating more vacuum and drawing the slides up sooner which would cause a lean condition.
I am waiting on the rudimentary air/fuel monitor setup to arrive.
If that doesn't produce readable data a full on data logging system will be next. In the meantime the 02 sensor port will be welded on.
No more guessing.
 

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W custom stuff it will require custom jetting. Try stepping up the main a few sizes and see where that gets u. To tune a carb from scratch u gotta get the idle right, then WOT, then experiment with needles/shims/slide hole to get the midrange and part throttle. And changing anything changes everything to some degree. But u r at the point of experimentation. Might see if u can look up the carb setups for a zx10, zx11, zrx12 (or zzr12) and draw up some ideas from what they run, both stock and modified. Good luck
Only reason I mentioned what I did, cuz after I installed a Factory Pro kit in my ZX-11, it did EXACTLY what OP did, started dropping off over 8 grand. Called FP. They said add another shim or 2. Thats what I did and Viola!! My thinking is a larger MJ would be like a hammer to a fly, when all u need is a lil nudge to be where u want to be. 8-11 grand just needs that needle to be a bit more out of the MJ to deliver da gas that the rpm range needs.

With this being said, thats why I dont like Dynojet. I dont like drilling the slides either. FP's jet needles have a different taper then OEM, AND they supply a totally different spring to go with said Needle. Works like a charm
 

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Discussion Starter · #13 ·
Only reason I mentioned what I did, cuz after I installed a Factory Pro kit in my ZX-11, it did EXACTLY what OP did, started dropping off over 8 grand. Called FP. They said add another shim or 2. Thats what I did and Viola!! My thinking is a larger MJ would be like a hammer to a fly, when all u need is a lil nudge to be where u want to be. 8-11 grand just needs that needle to be a bit more out of the MJ to deliver da gas that the rpm range needs.

With this being said, thats why I dont like Dynojet. I dont like drilling the slides either. FP's jet needles have a different taper then OEM, AND they supply a totally different spring to go with said Needle. Works like a charm
With the needle any higher it runs too rich in the midrange.
Yesterday I did a run on a closed street and hit redline, the issue of running lean occurred on the freeway after running for an extended period. I am now pretty sure the float bowls were low on the freeway. A cheap fuel pump arrived the other day which I will use for diagnostics (02 sensor & gauge is still on the way).
 

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With the needle any higher it runs too rich in the midrange.
Yesterday I did a run on a closed street and hit redline, the issue of running lean occurred on the freeway after running for an extended period. I am now pretty sure the float bowls were low on the freeway. A cheap fuel pump arrived the other day which I will use for diagnostics (02 sensor & gauge is still on the way).
A mal adjusted float will definitely do that. Fuel levels dont get replenished fast enough @ contued high spped throttle openings
 
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Discussion Starter · #15 ·
I don't want to run this $10 fuel pump for an extended period.
Literally every aftermarket motorcycle pump on Amazon has negative reviews for leaking, slowing, and failing altogether. I'm open to suggestions for an OEM pump that can be easily adapted to mounting, preferably with inlets on the same end.
 

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I don't want to run this $10 fuel pump for an extended period.
Literally every aftermarket motorcycle pump on Amazon has negative reviews for leaking, slowing, and failing altogether. I'm open to suggestions for an OEM pump that can be easily adapted to mounting, preferably with inlets on the same end.

Another good used example.

Here's some more:
 
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Discussion Starter · #17 ·

Another good used example.

Here's some more:
Thanks for the suggestions 👍 if my carbs don't overflow with the cheap pump I'm upgrading to the ZX series.
 
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