Right people, I've been reading through all the old posts re. ZX9R bike carbs, as I've got to the stage of getting mine going. However, there's a lot to take in and I'm struggling!

As it stands, the carbs are standard and I've not touched them at all. I bolted them onto the inlet manifold and previously had the Zetec ticking over using the bike fuel pump, but it died as soon as you touched the throttle. Now having done my research on here, I'm supposed to adjust the mixture screws underneath, re-drill the main jets out by 0.05-0.1mm from standard, and maybe put a washer or two on the main needle, is that correct? But I've also read that you're supposed to block off one of the air jets on the front face where the filter goes. But I have no idea which one that is. I've definately got the fuel pipes connected correctly, the water pipes blocked off, and the top breathers open and facing upwards.

If anyone has any pictures of the mixture screw location, or pictures with more precise details, it'd be much appreciated.


PS - I believe they're from a ZX9R C model, and are mint having covered only a few hundred miles from new. They've yet to be balance don account of the low mileage as well. If anyone ha any recommendations for a manufacturer of a plenum (?) chamber or filter design, then it's much appreciated as there's too many options - socks, sausage filter, plenum etc.

Make sure the diaphrams are sealed, blipping the throttle should make them all rise together.

The air jet to block is the one in the middle in line with main jet. I'm sure there is a picture someone on here has that shows you the right one.

Mixtures screws are underneath the carbs inside longish tubes.

Balancing is quite critical as well. First stage of tuning should be getting the balance correct at tickover. That will help smooth running but really a go on gas analysis machine on a rolling road is the best way to set them up.

Mine has 1.8 mains, mixture screws out 4 turns, needles 1 groove down from the middle. I have them wide open because he plenum and canister filter system robbed loads of power.

Hope that helps
Steve

is this any help, can't 100% remember which i blocked off on the BEC, i think its the one at 12o'clock


Jet locations in float chamber

[Edited on 3/6/09 by MK9R]

[Edited on 3/6/09 by MK9R]

You mean the hole directly above the main jet?

What's the best way to do this, through tapping the hole and inserting a small bolt etc., or a more permanent approach?!?

quote:

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Originally posted by Charlie_Zetec
You mean the hole directly above the main jet?

What's the best way to do this, through tapping the hole and inserting a small bolt etc., or a more permanent approach?!?

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Confirmed. It's the one at 12 o clock to the main jet. The dynojet kits comes with a tiny brass piece which is just glued into the hole so summat similar.
Whilst you've got the bowls off it'd be worth removing and just cleaning the fuel filters at 6 o clock to the main jet. You can see that they're just held in by the side of that screw head. Mine were a bit gungy.

Hi the air hole that bogg brothers blocked on my car is the one in line with the main needle [ the top brass hole in my photo boggs used 2.5 alloy welding rod to do this

carbs on manifold

[Edited on 3/6/09 by jacko]

Wait! Jacko's right. I bleeding knew there was something wrong and even went out and had a look at my carbs removing the needles as I was sure that the air hole couldn't be in the fuel bowl. My fault. Jacko to the rescue.

Right, well I've posted some pics of my carbs to my archive. They're marked ZX9 C, but I've ordered 2 airboxes from fleabay described as fitting this exact model, and both have arrived with different mounting plates. Neither of which fit.

I know I'm going to have to get a sausage filter for them, there's no question about that now. But does anyone know what carbs they are?

I've made note of the above comments, and intend to block off the airways nearest the opening on the air filter side of the carbs, and also need to adjust the mixture screw underneath (guessing that's the one with the plastic cover over it- missing one at the moment!). How many turns should I need to give it to get it running? Once it's under way, I've got access to some mercury guages to balance them.

Slowly getting there now, I think....

Looking at your photos you have b/c carbs


[Edited on 9/6/09 by jacko]

hi mate,you might need a presure reg,i did with mine and i have a bike fuel pump,when you start it and it dies take a plug out and see if its wet if so floodings your problem,
one thing i will say,is that i blocked off that air hole thats inline with the main neadle,and when i was on my way to the iva it was running far to rich,splutting ,so i unblocked them and it was fine,these are std carbs,thay have just had the main jet drilled to 1.6mm,i think some kits have for them have to block those holes but for me it worked better with out them blocked

Thanks for all the input, guys. I think I'll leave the airways open for the time being then, and see if I can get it to run. Might even try a touch of bluetack over them just to see if it makes a difference.

With regards to the pressure regulator, I've currently got the bike fuel pump very close to the carbs for testing, would this afect it at all? What other regulator would you suggest I use?

The manifold should be finished by this weekend, so maybe a touch of back pressure might assist. And I'm gonna wind the mixture screws underneath (I'm guessin that's what they are) right in and give them a single turn out, see if the new mixture helps.

Gets a bit annoying sometimes, as we've had it ticking over before. And it's not like I'm near enough to Bogg Brothers to get them to sort it all out either!

hi mate,my pump is ment to have a reg built in but it still was flooding,so i got a fuel reg from merlin only 20quid i have it set to 2.5-3psi,this done the trick,now if you block the holes you wont notice any diffance if your at idle,its when you drive and use the main neadle thats when you will notice it

If you have the right bike pump you will not need a regulator if its flooding check the float needles are ok and working and the float height is right

I got a matching bike pump from the same bike, as it all came from a single donor vehicle at the specialist breakers near me.

Might be worth me reading up on the float chambers etc. and checking the plugs after running, see if it's over or under fuelling.

Aside from that, does anyone know of any tuners in the Essex area who are knowledgeable in setting up and tuning bike carbs?