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Carb needle settings.

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Brian.:

--- Quote from: Bryanj on July 29, 2020, 10:24:58 AM ---Only mention i can find is page 178 which is the K3 supplement and refers to PD carbs and its 3rd groove for 550 but 2nd for 500(K3 500 never came to UK  officially).

There is also a carb setting table on page 165 (550F-A) which i find confusing.

--- End quote ---

Thank you Bryan; yes I saw that too from what I've read on here the PD carbs on the K3 are not like mine so I disregarded it.

Brian.

paul G:
Found this topic but it may well be worth contacting Gerben on this forum to confirm.

http://www.sohc.co.uk/index.php?topic=19413.0

deltarider:

--- Quote from: Bryanj on July 29, 2020, 10:24:58 AM ---There is also a carb setting table on page 165 (550F-A) which i find confusing.

--- End quote ---
Rightly so. The Shop Manual Honda CB500 - CB550 clearly has an error on that page 165. https://www.classiccycles.org/media//DIR_1653304/DIR_1653404/DIR_1653507/ecc6759db0a214d5ffff8824ffffe41e.pdf
Over the left column in the Carburetor setting table you should read CB550 and not CB500.
Not only would it be unlogic to compare CB500 and CB550 carbs on that page - and perfectly logic to compare CB550K carbs to CB550F carbs - also... no CB500 models ever had the 022A carbs.
Now to the question Brian has posted. The standard position seems to have been 4th from top. Source is an America Honda booklet with carb settings for several Honda's.
BTW, based on all the info I was able to find, I have compiled an overview myself. I have limited my search for the oldstyle carbs like you have.

Brian.:

--- Quote from: deltarider on July 29, 2020, 11:14:35 AM ---
Now to the question Brian has posted. The standard position seems to have been 4th from top. Source is an America Honda booklet with carb settings for several Honda's.
BTW, based on all the info I was able to find, I have compiled an overview myself. I have limited my search for the oldstyle carbs like you have.

--- End quote ---
Thank you Deltarider.  I'm surprised it's fourth from the top!  This would then raise the needle.  That will make it run richer than first, second or third groove, won't it?  I would have thought that with US awareness of emissions in the 1970s that it would be weaker if anything.  Maybe I'm wrong about that.

Thank you very much for replying.

Regards, Brian.

deltarider:
Brian, forsaid booklet is an edition (1977) by American Honda Motor Co., Inc. But... also p.165 in the Shop Manual Honda CB500 - CB550 gives us some indication. Have a close look at both columns, if you like, where the carbs are further specified. In the third line we read in the CB500 (which should be CB550(K)) column: '4 grooves' and in the CB550F-A column '2 grooves'. Read so, this is incorrect, because the CB550(K) actually had 5 grooves and the CB550F models had 4. Now what if this has been a clumsy translation by some Japanese Honda clerk who has struggled with English? I mean if we read: 4th groove and 2nd groove respectively, the information is correct.
Now a sidestep to the CB500. That same booklet specifies for the US CB500 an airscrew opening of 2 turns out and the needle in 4th position, where in Europe the CB500 had 1 turn out and the needle in 3rd position.
My explanation is as follows. Having seen the smog above Los Angeles in the early 70s with my own eyes, it was clear, authorities had to respond to this. I seem to have a vague recollection that they have started by reducing the harmful emissions at idle. As you know, the early CB550 models with oldstyle carbs have not been exported to Europe. However, if they had been imported here, we can't rule out the carb setting would have been: one turn out and needles in 3rd position, analogue to the choices they had made with the CB500 before. So it's your choice. :D

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