Fuel/air mixture

random_rob · Two Stroke Sniffer Joined: 16 Mar 2010 Karma :

how do you set the fuel/air mixture along with the idle screw, as when i turned up the idleing the bike had no power when i went to accelerate, then all of a suddedn it would come at once.
any suggestions?

Wafer_Thin_Ham · Super Spammer Joined: 18 Nov 2005 Karma :

Where do you want to chance the fuelling?

Idle is controlled by the idle screw, the middle of the range is controlled by the needle, and the upper part is controlled by the main jet. (I think, I'm not so great with carbs)
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random_rob · Two Stroke Sniffer Joined: 16 Mar 2010 Karma :

theres only 2 screws, a big one which i think is fuel/air mixture and another which is smaller and hard to get to which i think is the idleing.
when someone strips down a carb then rebuilds it, i just wondered how they set it all back up.

Vincent · Banned Joined: 16 Oct 2006 Karma :

Frost · World Chat Champion Joined: 26 May 2004 Karma :

There will be an idle screw that sets the rev's when the throttle is closed, basically acting as a lower throttle stop. Then there is the mixture screw. This adjusts the ratio of fuel to air. It's normally used to get the bike to pass emissions tests in various countries. The UK had very reasonable emissions rules so just set it to what the UK manual says and it will be fine. You can put it a bit richer if you've got problems with the power delivery being snatchy, but go too rich and you'll be going slower whilst using more fuel and fouling plugs all the time.

Normally you set it to however number of turns OUT. So you screw it all the way in, then turn it out say 1.5 times.

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

Changing the idle mixture adjustment screw will have virtually no effect at all on the mixture when you crack the throttle open.

All the best

Keith
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Odie · World Chat Champion Joined: 24 Jul 2004 Karma :

random_rob · Two Stroke Sniffer Joined: 16 Mar 2010 Karma :

ahh right, that would explain alot.
how do i know if the mixture screw is set right?
ive got it to run on tick over now, but doesnt seem to be as quick.
the air mixture screw is difficult to get to.

steveh · World Chat Champion Joined: 24 Aug 2004 Karma :

what bike is it?
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random_rob · Two Stroke Sniffer Joined: 16 Mar 2010 Karma :