Carb Air/Fuel Mixture Query

[Bongoball]

Evenin' Chaps,

On my Z650 I've got Mikuni VM29's that have a screw on the side for altering the air mixture: -
Spark plug too black; mixture too rich - turn screw out to allow more air.
Spark plug pale; mixture too lean - turn screw in to reduce air.

Now on my Z1000A2's carbs, there is a little knurled screw below each carb body.
I read last night that this alters the fuel mixture, not the air mixture.
The question is, is the procedure to adjust the mixture the same as my smoothbores?
i.e. turn screw in to reduce airflow, out to allow more air.

Your thoughts please gentlemen.
Bongo.

[Pigford]

Usually (but not Gospel) - if screw is before needle (at rear of carb nearer air filter) then its an AIR screw - out to weaken..........


........ if its forward of needle (nearer cylinder head) then its a FUEL screw - in to weaken

[Bongoball]

OK, here are a couple of pix just to save any confusion.

Side on (taken from same side)



From underneath (taken from kerb side)




As you can see, the screw is towards the engine.
Does this mean, as you've said, it's in to weaken?


Bongo.

[Pigford]

YEP.... thats a fuel screw - so in to weaken

[Bongoball]

So thats opposite to the VM29 smoothbores, which turning the scew in would reduce air flow making mixture richer?

[pertonpc]

Hi Bongo

That's the same screw position as my standard 650 carbs.

Screwing them in makes it run leaner on mine.

Cheers from Mark

[Bongoball]

Thanks guys, that's a great help.

[GPRD]

When you get a knack of adjusting them without burning your hands, can you let me know please.

[pertonpc]

Try this -

Starter motor cover removed for more clearance

Thick cotton gloves to heat proof your mitts

Use slot driver bit fitted to tubular adapter (not full screw driver) and mark the tube with lines at 1/4 turn intervals to help you measure.

Select the biggest slot bit that will fit the screw whilst it is all cold.

Voila - no singed donnies (well I didn't anyhow)

[GPRD]

Cheers, I'll try that.

[z1bman]

fuel mixture adjuster tool

http://www.ebay.co.uk/itm/NEW-MOTORCYCL ... 874wt_1037