View single post by Esprit2
 Posted: 05-11-2023 07:09 pm
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Esprit2

 

Joined: 05-01-2005
Location: Minneapolis, Minnesota USA
Posts: 574
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Be careful about using an O2 sensor/ AF meter to tune carbs. Those tools will lead you to a chemist's version of perfect combustion, a stoichiometrically correct air/fuel ratio. Perfect combustion... depending upon whose definition of 'perfect' you use.

Neither the 907 nor Dellorto carbs ever studied chemistry in Grad School, and neither gives a darn about a stoichiometrically correct mixture. If you wish, use it as a starting point, and tune from there toward a better mixture, then go for it. But don't get your hopes up that a 'by-the-book' stoich mixture "end goal" is going to make your 907 run well... regardless of which brand of carbs are installed.

As a kid, did your Mom ever try to give you a medicine that some doctor said was good for you, but it tasted like rancid crap and you fought her every inch of the way? Okay, now you're Mom, using an O2 sensor/ AF meter instead of a spoon to force a stoichiometrically correct mixture down your kid's... er, down your engine's throats that it does not like.

Be conservative about how you use an O2 sensor with carbs. There is no 'intelligent' ECU between the sensor and the engine, moderating the O2 sensor's signal into an "appropriate for the engine" carb setting. And your engine won't be happy with stoichiometrically correct, 'cuz it "tastes like crap".