Ninja 250 Carburetor Needle Information: Difference between revisions

Line 1:

=Background=

~~The needle in a carburetor is the main method of adjusting the mixture~~

~~at partial throttle openings. It blocks some of the passageway to the main~~

~~jet, reducing the amount of fuel which is able to flow during~~

~~partial-throttle operation, thus leaning the mixture. As the slide~~

~~raises, the needle is pulled further out, until at full throttle, it's~~

~~completely clear of the jet, allowing the full amount of fuel to flow.~~

~~The needle is tapered, so that as it's pulled further out of the main~~

~~jet, it blocks less of the port, and more fuel is allowed to flow.~~

The needle in a carburetor is the main method of adjusting the mixture at partial throttle openings. It blocks some of the passageway to the main jet (the main jet size determines the carb's overall mixture), reducing the amount of fuel allowed to flow at part throttle. This keeps the mixture consistent through a range of throttle openings: as the throttle opens, raising the slide, the needle also raises (it's attached to the slide). The needle has a tapered profile, so that as it pulls out of the main jet port, it blocks less and less of the port, allowing more fuel to flow, ideally matching the amount of air flowing through the carburetor. By the time the carburetor is at full/wide-open throttle, the needle is completely clear of the main jet port, allowing it to flow without restriction.

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 =Background=
-The needle in a carburetor is the main method of adjusting the mixture
-at partial throttle openings.  It blocks some of the passageway to the main
-jet, reducing the amount of fuel which is able to flow during
-partial-throttle operation, thus leaning the mixture.  As the slide
-raises, the needle is pulled further out, until at full throttle, it's
-completely clear of the jet, allowing the full amount of fuel to flow.
-The needle is tapered, so that as it's pulled further out of the main
-jet, it blocks less of the port, and more fuel is allowed to flow.
 The needle in a carburetor is the main method of adjusting the mixture at partial throttle openings.  It blocks some of the passageway to the main jet (the main jet size determines the carb's overall mixture), reducing the amount of fuel allowed to flow at part throttle.  This keeps the mixture consistent through a range of throttle openings: as the throttle opens, raising the slide, the needle also raises (it's attached to the slide).  The needle has a tapered profile, so that as it pulls out of the main jet port, it blocks less and less of the port, allowing more fuel to flow, ideally matching the amount of air flowing through the carburetor.  By the time the carburetor is at full/wide-open throttle, the needle is completely clear of the main jet port, allowing it to flow without restriction.