UK Karting - Notice Board (2-Stroke Karting) : Re: Why on earth do you want to know?

Notice Board (2-Stroke Karting)

Re: Why on earth do you want to know?
Posted by 'John' on 27 Jan 2011 @ 02:49

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JohnJoined: August 2001
Total Posts: 1
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Under normal working conditions the vacuum (airflow) gets weaker the further you move away from the engines piston. Also when moving away from the piston the first carb hole is the idle hole, then the progression port hole, then the needle slide and then the mainjet atomiser.

Each individual circuit is powered by the venturi vacuum (airflow) so, as a direct result of this pressure gradient, the first circuit to work will be the idle circuit as it is closer to the engines piston and then the progression port and finally the mainjet jet atomiser.

The carb is designed such that with the throttle slide closed the vacuum is only strong enough to power the idle circuit, the progression port, which is connected to the idle circuit takes in air which actually weakens the idle fuel flow.

As soon as the throttle slide is opened the vacuum increases which then draws fuel from the progression hole and finally as it opens even further the mainjet atomiser.

This performance profile, idle/progression/mainjet, is also controlled and modified by the shape and size of the throttle slide cut-out which is why Dellorto offer a number of different designs.

Message Thread:

Dellorto progression port flow reverse? by 'JonWright' (26 Jan 2011 @ 13:50)

Re: Why on earth do you want to know? by 'John' (26 Jan 2011 @ 19:45)

Re: Why on earth do you want to know? by 'JonWright' (26 Jan 2011 @ 21:20)

Re: Why on earth do you want to know? by 'John' << You are here!

Re: Why on earth do you want to know? by 'JonWright' (27 Jan 2011 @ 13:28)

Re: Why on earth do you want to know? by 'John' (27 Jan 2011 @ 16:35)

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