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Bike carbs - Outer 2 running rich?


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#1 danosborne661

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Posted 13 June 2017 - 10:31 AM

Hey all, few details on what I've got to start with

- 2.0 16v ABF
- Kawazaki ZX9R carbs (Keihin CVRs)
- Was running 180 jets - way too rich no matter how I adjusted the pilot screw (spark plugs were sooty)

Now I'm running 170 jets with the pilot jet adjusted to 3 turns out to lean it off, the inner 2x spark plugs are now a decent bronze colour, the outer 2 are still looking very black!

What should I do? Would it make sense to go to a 165 jet on the outer 2x carbs? Would it be a strange adjustment to lean off the pilot jets on JUST the outer 2 carbs?

Cheers all :)


Edited by danosborne661, 13 June 2017 - 10:33 AM.


#2 adam-

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Posted 13 June 2017 - 11:44 AM

Get a wideband and log fuel at all RPMs. There shouldn't be that much of a different between individuals; but usually two run richer than the other two. Can't remember if it's inner or outer though.

#3 Chaz!

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Posted 14 June 2017 - 07:15 AM

When I had my R6 carbs and I went to change the jets I found that the inner two were larger than the outers from the factory, so I stuck with that when I increased the size and they ran fine, they were Keihin too iirc

 

Edit: Also what engine? Mine was a 1.4 AFH


Edited by Chaz!, 14 June 2017 - 07:16 AM.


#4 danosborne661

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Posted 14 June 2017 - 04:15 PM

Hey guys,

Thanks for your help and good to know Chaz.

I'll get some 165 jets so I'll running 170 on the inside and 165 on the outside!

It's a 2.0 16v ABF



#5 Keeha

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Posted 16 June 2017 - 06:30 AM

I'd try making the existing ones a bit leaner first, it's what the screw is there for.

And yeah they nearly always have odd sized jets from the factory :)

Edited by Keeha, 16 June 2017 - 06:30 AM.


#6 danosborne661

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Posted 18 June 2017 - 11:03 PM

Hey Keeha,

I tried leaning it out a lot on the pilot jet and still running very rich! The pilot adjustment is only for idle to quarter throttle anyway so doesn't lean it through-out the entire stroke like a needle/main jet adjustment does.

I'll fit the 165's on the outer after Glastonbury and I recon that'll be good to go! Cheers for the advise all