Air/Fuel mixture screw

Hey guys much help would be appreciated, Ive always wondered what should i set my air screw mixture to on new carbs and how do you fine tune it so perfect never really found out thanks

 

You set the mixture screw to whatever the engine want's, start it up and run until the choke is off, then adjust the mixture screw in-out until it ticks over at it's smoothest/fastest, then adjust tickover to suit.

 

thanks very much

 

Thanks jonny thats helped alot top man!

 

3 and a quarter? mine has a 21mm inlet manifold standard carb and big one exhaust, what should i set the fuel air mixture screw to?

 

Well my ped bogs down when I try to ride and all I've done is cleaned the carb and fitted a 1mm bigger jnlet

 

The 1mm bigger manifold is the problem? What can I do to solve it?

 

see like I said inlet wont make any difference its probably mixture screw if it's bogging at quarter throttle or a air leak from not refitting manifold or carb properly

 

Right, well I checked the fitting of the manifold and the carb and that's fine it's tight, so the only other explanation is the fuel air mixture yes?

 

I'd say so, like you said your mates probably messed with it

 

Yeah, I've spoken to all my freinds and their all saying it needs up jetting so I've purchased a 68 jet aswell, but I'm going todo my fuel air mixture tommorow morn too

 

well if you asked your friends what jet you need get one of them to help you get it running as they know so much

 

I am lol

 

I have up jetted to a 68 main jet and it now rides fine, but it is a bit spluttery and struggles a little I'm thinking its the fuel/air mixture needs adjusting, shall I set it to factory setting?

 

when does it splutter is it full throttle or what mate

 

It splutters at low throttle but when it revs up it's fine

 

yeah be your mixture screw setting

 

Ah righto do you think I should set it to factory setting again?