Topic Approved and moved to Help Section.

This is the CBZ Xtreme's screw but I couldn't get original CBZ's pic anywhere:

Thank you Samarth for the post. I shall try and upload a few pics of my cbz's carb.

Hi buddy,

You might wanna check out this thread too: http://www.xbhp.com/talkies/help-me/...w-my-carb.html

Hope it helps.

Here i have attached the Left side view of the carb. The idle screw is on the right.

I have marked one box as a question mark. Could that be the A/F mixture nut?

Thank you Plasmabhai for the post. I also went through the video in this thread. So this Air / Fuel mixture is infact two separate screws. The idle screw controls the air flow and the other one controls the fuel flow. Hope i have understood correctly.

Because till today i was thinking that it is one and the same thing and the idle screw just controlled the number of RPM's nothing else.

From the picture you have put up, I dont feel that is the AF mix screw. But I am not sure, hopefully other experts should be able to clarify. Can you upload the picture of the other side too? Or is it covered by the black plastic cover?

Idle screw indeed just controls the RPM at idle. It does not do anything to AF mix at all. So you had that part right.

For setting the AF mix, there is only one screw on any carburettor. Either that screw controls the amount of air going in the mixture, in which case its called the "air screw", or else that screw controls the amount of fuel going into the mixture, in which case it is called the "fuel screw".

One hint is that normally if your carb has an "air screw" then it will be located towards the air filter side. If the carb has a "fuel screw" then it will most likely be located near the engine side.

And, logically, if you unscrew the screw (i.e. turn it anticlockwise) then more air will go into the mix in case of "air screw", therefore leaner mix, or else more fuel will go into the mix in case of "fuel screw", therefore richer mix.

Leaning out the mixture results in the fall in idle rpms and making the mix rich means that idle rpm rises and then starts fluctuating which means that the mix has become too rich.

Most modern carbs have "fuel screw" like shown in my pics and Samarth's pics. In your case, like I said, am not too sure. But posting a pic of the other side will help other people to clarify.

Ok found the AF nut. it is the one marked with question marks in the image above.