Beta 125 Evo Carburettor Setting

[malcolm]

Can anyone advise what is the correct setting for the air screw on the carburettor on a 2013 evo 125. I stripped and cleaned the carb but forgot to count the number of turns before I removed this screw.

Thanks

[overdale]

Providing that your carb has standard jets, most likely 55 pilot, 130 main and needle clip in 2nd slot from bottom (2nd richest) try the airscrew 2.5 turns out from fully closed to start with. I've known them to have good carburration at anything between 1.75 and 3.5 turns open.

[malcolm]

Thanks overdale. After turning it 2.5 turns out what is the procedure to set the screw at the correct position?

[overdale]

The exact setting of the airscrew can be found by seeing what the response of the engine is to any change in position. Think of the airscrew is just a simple valve ,when it is closed ( fully clockwise ) no air flows , when you open it anti-clockwise more air flows the more you open to mix with the fuel from the pilot Jet.

If the mixture is weak the tickover usually gets faster, if too rich ( not opened enough) the bike will not pick up cleanly, splutters under acceleration and may need revving to clean it out.

So start at 1.5 turns open from fully shut, adjust the tickover screw if necessary for a steady tickover, then see what the response is when you open the throttle. Progressively open the airscrew 1/4 turn at at time until it pulls the cleanest and smoothest without hesitation under load.

From my experience, many spluttering bikes at trials are caused by their owners never removing the airscrew to blow through the pilot air passages to keep them clean.

Hope this helps!

[malcolm]

Thanks overdale.