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Old 11-27-2012, 02:57 PM
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GearNut GearNut is offline
Motorized Bicycle Elite Member
Join Date: Aug 2009
Location: San Diego, Kaliforgnia
Posts: 5,106

Most all engines need the clip position tuned. The "better" carbs you speak of really should have adjustable slide needles.
Atmospheric conditions such as the altitude you live at, outside temperature, and more, all have a big impact on the engine's state of tune. Changing the jets to tune a carb is all fine and dandy, however it re-calibrates the fuel to air ratio in large jumps. Adjusting the slide needle allows even finer adjustments when combined with tuning the jet size.

Just because these "better" carbs don't give you the ability to tune the needle position does not mean that they don't need it. Quite the opposite actually.

It is that fact about them that I have issues with calling them "better".

Most of them have been released after the EPA and CARB Nazis tightened up the import restrictions even more and now the factories are required to "pre-tune" the engines to pass the import exhaust emissions standards requirements. They use fixed position needles and capped (sealed off) low speed mixture screws to try to prevent the end user from re-tuning the engine and increasing the unwanted emissions. This is all done by import law, not necessarily by the factory's choice or preference.

The whole notion of a "pre-tuned" carburetor is horrible!
Just ask anyone who lives up in the hills how well an out-of-the-box engine runs.
Ask them to never ever tune the engine, no matter the reason.
Will they be happy with it? NO!
"It's a chinagirl. It's a sometimes fun little engine that often will break your heart. It's disposable.

Does not come with a fortune cookie."
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