Author Topic: Cb550f carbs rich or lean air screw question  (Read 515 times)

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Offline Can550

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Cb550f carbs rich or lean air screw question
« on: August 27, 2019, 01:55:53 PM »
Manual calls for 1 1/2 turn -+ 1/2 turn. Question is from 1 1/2 turn, will IN make it rich or OUT ?
Thanks


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Offline 05c50

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Re: Cb550f carbs rich or lean air screw question
« Reply #1 on: August 27, 2019, 02:28:01 PM »
In leans the mixture.

...Paul
Wear a helmet,the life you save may be your own.Ask me how I know.               CB650C,CB550F,GL1000,CB750A

Offline TwoTired

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Re: Cb550f carbs rich or lean air screw question
« Reply #2 on: August 27, 2019, 03:13:27 PM »
On all my 550 Fs turning the air screw outward leans the mixture.  Verified with an exhaust gas analyzer.  Applies to 627B, 022a, 069a series.

Does not apply to PD carbs, which operate opposite.

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline maxheadflow

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Re: Cb550f carbs rich or lean air screw question
« Reply #3 on: August 27, 2019, 03:44:53 PM »
It depends on the carb.  For slide type, if the adjustment is on the air cleaner side from the slide, turning it in richens. If the adjustment is head side of the carb, turning it in leans.    (Typically)   I know the 76 cb550f  had had them on the  air cleaner side. 77-78 might have changed to the other side as the CB750s did.