Throttle slide -SCOOTER CENTER- for Dellorto / Spaco SI24/24 E/H Vespa PX200, Cosa200 -

Air pockets
The PX200's original throttle slide has a large radius (often incorrectly called a cutaway) on the underside (side facing the crankshaft). This bag allows the carburettor to provide a controlled supply of air to the carburettor at medium stroke to lean the mixture.

The sliders are therefore available in three versions.

• 4.0 - Open = like original = lean
• 4.1 - 50% closed = slightly fatter than original
• 4.2 - 100% closed = significantly fatter than original

If the motor rings slightly in the partial load range with the slider in the middle position, changing to slider type 4.1 can help. The engine then runs a bit fatter in this area.

Engines that run too lean in the middle area or don't need supply air (original e.g. Rally200 and Cosa200 original), use the type 4.2.

Cutaway
All sliders have in common the small middle cutaway at the beginning of the slide surface. This is important for the throttle response on the first millimetre of the slide stroke. If the angle of attack of the cutaway is changed (filed) here, the resulting negative pressure and thus the response behavior can also be changed.

FAZIT: Nice part to make the fine tuning perfect. Ideal to get powerful SI-based motors well tuned even at high speeds and low slider stroke (motorway!).

(US)