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[sorted] ZX6R F series not ok between 4-7k rpm but good between 1-4k and 7k to redline

850 Views 52 Replies 5 Participants Last post by  Brandon35
Hello everyone,

I have an F series ZX6R and I am unable to figure out what is wrong... Can someone help me? 馃槵

Here is the situation:
Idles normally.
I can readline the bike in neutral and I do not have any weird behaviour.
I can readline the bike in 1st gear OK and in 2st gear with a slight moment of hesitation at 5k rpm and will reach 7k and goes to the red line perfect.
Then I can pass 5 6 7 k at third gear albeit with a lot of misfires and cutoffs and then off I go to red line.
On fourth gear and above I can't pass 5k it will misfire too much and throw me forward and backwards.
Last thing: when I go to red line say in third gear but decelerate (whilst leaving the throttle 20% open) (staying in 3rd gear) and enter the zone 7-6-5-4k it seems to accentuate the issue the engine start to burble, bog down, sort of misfire or was starving for fuel.

Things I've done:
I've cleaned the carbs
New sparks
New ignition coils.

Things I have not done:
Compression
Valve clearance
Check the rest of electrical system

Because of the weirdness at 5k my suspicions went to the transition from pilot jet to needle jet and the diaphragms. I've checked again and again if not pinched or whatever but everything is installed ok...

Any help is appreciated 馃憤 please.

Thank you!!!!
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Hi there,

Thank you so much Brad and everyone for your help.

So it is all sorted now.

Bottom line:
  1. The issue at 4-7k range was due to the vacuum pipe between carbs and air box being defective.
  2. The issue at 9k that I had was related to the air filter being overloaded by oil.
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Hi there,

Thank you so much Brad and everyone for your help.

So it is all sorted now.

Bottom line:
  1. The issue at 4-7k range was due to the vacuum pipe between carbs and air box being defective.
  2. The issue at 9k that I had was related to the air filter being overloaded by oil.
Glad you got it sorted.
Much useful information embedded in this conversation鈥.
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I just realized that your handle bar clamps are positioned way more straight; aka either you or a previous owner drilled and tapped new holes in the top triple clamp for a more "ergo" handle bar position.

Wicked.
I just realized that your handle bar clamps are positioned way more straight; aka either you or a previous owner drilled and tapped new holes in the top triple clamp for a more "ergo" handle bar position.

Wicked.
I noticed that too but there isn鈥檛 any old holes shown. Thought maybe I was just seeing it wrong.
I noticed that too but there isn鈥檛 any old holes shown. Thought maybe I was just seeing it wrong.
If you zoom in, the origional holes are partially visible near the top of the triple poking out from the fork clamps
If you zoom in, the origional holes are partially visible near the top of the triple poking out from the fork clamps
Ahh ok. The zoom on the Mobil is crazy. Instantly goes to insane zoom on my phone. Hard to see.
Ahh ok. The zoom on the Mobil is crazy. Instantly goes to insane zoom on my phone. Hard to see.
Same here, took me very many swipes to get to the right spot on the picture lol.
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I did it but then i had trouble with the upper fairing that I had to grind down 'nicely' (its a track bike so im not too concerned but if youbare worried about looks it is goong to be a challenge) and also the instrument cluster will touch the handle bars at 3/4 travel so I had to but a new instrument cluster... if you want to keep the oem youll have to modify the metal braket instrument holder....

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I did it but then i had trouble with the upper fairing that I had to grind down 'nicely' (its a track bike so im not too concerned but if youbare worried about looks it is goong to be a challenge) and also the instrument cluster will touch the handle bars at 3/4 travel so I had to but a new instrument cluster... if you want to keep the oem youll have to modify the metal braket instrument holder....
Oh trust me, I have plenty of practice modifying the guard/headlight stay. Hence why I don't have the bird cage anymore.

Probably wont do this mod unless I bought new/non OE clamps that are adjustable but kudos for making it work.
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Oh, can I remove the birdcage altogether without the risk of the fairing collapsing at high speed?
Oh, can I remove the birdcage altogether without the risk of the fairing collapsing at high speed?
No; I welded in my own mirror mounts to the stock gauge/headlight stay; I cut the mounts from a steel ZZR fairing stay and mocked them up to my bike.

I didnt have steel TIG Rods the time so I did it with stick and regret that. TIG would have been far easier and cleaner. I'll snap a pic later.
2
Forgot to take pictures the other day; here's my setup for the fairing stay. No more birdcage, again welding in my own mirror brackets to the OE gauge/headlight stay.

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