Factory Pro said:
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CV Carbs: Too RICH at full throttle / low rpm (that's the most common in CV carbs)
Slide carbs (FCR's) - Float height controls 25% throttle at ALL rpms.
If the float height is too low (small float height measurement), bend the tab slightly to increase the height measurement. It's a 5:1 movement ratio.
CV: If the float sticks out further, down, into the float bowl, the carb will deliver less fuel (leaner), especially at low rpms and at cruise.
Slide carbs: Float height controls 25% throttle at all rpm's, even at redline.
You'd generally change the float height in 1mm increments when tuning. It will affect the topend slightly. Maybe 1.5mm leaner float height would require 1 size larger main jet to keep equal main jet fuel delivery.
CV Carbs: Too LEAN at full throttle / low rpm (not too common in CV carbs)
Slide carbs (FCR's) - Float height controls 25% throttle at ALL rpms.
If the float height is too LARGE, bend the tab slightly OUT to decrease the height measurement.
If the float sticks out further, UP, into the carb body, the carb will deliver MORE fuel (richer), especially at CV low rpms and at cruise.
It will affect the topend slightly. Maybe 1.5mm richer float height would require 1 size smaller main jet to keep equal main jet fuel delivery.
You'd generally change the float height in 1mm increments when tuning.
When you are done, a multi-cylinder must be all within .5mm (1/2mm) or .020" range of each other.
The level in the float
chamber is therefore a calibration
element of the carburetor, since the
metered fuel delivery changes with
float level, and therefore affects the
mixture ratio. By having a high
float level, a greater fuel quantity is
delivered compared to the case with
a low float level, under all operating
conditions and for all of the carburetor's
circuits.
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