how to set up your carbs

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zxr400er
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Joined: Sat Jan 22, 2005 1:21 am

Re: how to set up your carbs

Post by zxr400er » Mon Aug 26, 2013 1:40 pm

I'm just setting up a set of carbs and I'm curious as to how you define lightly seated with the air screw?
Is this when it first make contact and you can feel light resistance or like I am doing and when it first has some real resistance (I.E when the spring has compressed)

Thanks

ross46
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Joined: Fri Aug 26, 2011 9:31 pm
My Bike: zxr 400 l6

Re: how to set up your carbs

Post by ross46 » Mon Aug 26, 2013 2:16 pm

You should be able to feel it, do it up till it won't really move without lots of pressure, sort of like fingertight, just do it up and you'll feel when its bottomed out

cloud9
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Joined: Sun May 19, 2013 6:57 am
My Bike: zxr400 L4

Re: how to set up your carbs

Post by cloud9 » Tue Aug 27, 2013 1:11 am

I've been having all sorts of issues with my L4 carbie wise,
a mate has a gas analyser that sniffs Air fuel ratio and was and is still running way too rich and after a full carbie clean , new needle and seats, new bowl gaskets new mixture screw O rings and new plugs , new fuel pump and K&N filter fuel filter new coils ad the list goes on .
this thread states the stock mains are #90 mine are #92 stock primary #35 standard needle at N77s and good diaphragms but it still runs rich and it seemed that less than 1 turn out from seated was somewhere in the ball park for the right AF ratio? ( by the sniffer)
the manual states the stock main as a #95 so which is the right stock main #90 or #95??
and was also told that the mixture screw was a fuel adjuster not an air adjuster which made sense for the way the screw reacted to being wound in to reduce the richness.
my carbies are keihin cvk D32's it's a un restricted bike without the chock plates in the throats of the inlet rubbers which I have also replaced with new ones ( rubbers)
have my bike booked in for a Dyno tune next Monday so any info prior to taking it would be sweet .
bike has had a few want to be racers own it before me and I am trying to take it back to stock for F4 racing here in oz I don't know if anyting has been drilled or engineered by joe mechanic.
in an attempt at gaining HP without doing a dyno run.
thanks in advance.

ross46
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My Bike: zxr 400 l6

Re: how to set up your carbs

Post by ross46 » Tue Aug 27, 2013 11:04 pm

Tried the analyser before, gas analyser, testo one £800 quid, we got it changed to do petrol, it didn't work, just get it on a dyno if you want perfection, with the analyser you can't really do it properly as you can't get the readings under load etc

japmannslim
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Joined: Mon Dec 26, 2011 6:22 pm
My Bike: zxr400l9
Location: Birmingham

Re: how to set up your carbs

Post by japmannslim » Sun Nov 03, 2019 8:24 am

Hi good guide, but i think you are incorrect with the pilot circuit. Dont forget that the screw is a fuel screw and therefore you turn it out to richen and in to lean.
Kind regards
Robin

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