Honda Carb experts?

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Pete808
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Honda Carb experts?

#1

Post by Pete808 »

Figured I would give it a shot here and see if someone can help me out. I know it's not a Harley but some of you guys have Hondas in your fleets. I recently put the carbs back together for the CB550 that I have but I made the mistake of taking a 3 month break in between and now when I put them back together I have 3 parts that I can't figure out where they go. Anyone have any idea what these things do and where they go on a CB550 carb? There are only 3 which leaves me to assume that there is 1 somewhere in one of the carbs or I lost it but either way I don't know where to look. I went back and took things apart to try and see where it could go but had no luck. The needle is just for a size reference in the photos. Thanks for any help
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Andygears
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Re: Honda Carb experts?

#2

Post by Andygears »

It would seem that it is a puck, possibly to go beneath the idle speed screw to intersect the angle surface of the throttle slide. As I recall those carbs, and 750 version, have to be static set with a drill rod to get all four slides at the same place with the cable adjusted so it pulls all four evenly. Then set all four while running with four vacuum gauges, somehow. Makes a one carb, one set of points seem easy.

Only guessing about the puck.
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Re: Honda Carb experts?

#3

Post by Sarre »

Hi Pete,

the brass screw-in needle thing is an airscrew, these should be inserted at the mouth of the carb and are intended to block of air supply to a fuel/air mixture canal. Turning these inwards enriches the mixture and turning these outwards leans the mixture, most effect of the air screw is at idle up to about 2.5K rpm out of my head; but you can google a chart for the effect of individual components on the performance of the carb.

I don't recognize that puck, Andy refers to flatscrewdrive threaded inserts, but this puck does not have threads nor do I see slot. Can't help you with that tiny thing.
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Re: Honda Carb experts?

#4

Post by Sarre »

Ah I didn't read that part of the needle being meant for size reference... :lol:
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Re: Honda Carb experts?

#5

Post by 59Panman »

Are you using Carb Stix to adjust the vacuum for the carbs? I owned a 75 550 and put a 16" rear wheel on it I found at the flea market for $25!
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Re: Honda Carb experts?

#6

Post by Frankenstein »

Hi, If I recall correctly, there should be 4 of those, and they go in one of the holes in the bottom of the main carb body. I think the one that the idle mixture jet screws into. To try to paint a picture, the bottom of the carb body has a couple of vertical parts of the body, a little larger in diameter than your "puck". The really large one has the main jet screwed into it. And I think, there's at least one or 2 smaller ones, one of which the idle jet screws into. And this puck fits into the lower end of that cast in "tube". A further hint is that the "puck" will be held into place by the float bowl when it's fitted to the bottom of the carb.
As for the missing one, you need to fabricate one from a rubber like product that will resist gas. Maybe an eraser?, one of those red rubber kind? A chunk of gas line? be creative. If I remember correctly , it plugs a hole that would otherwise be exposed to the gas in the float bowl and would totally screw up the carb gas metering systems.
Good luck!
DD
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Re: Honda Carb experts?

#7

Post by panhead »

Maybe you can find more info here: https://www.cmsnl.com/honda-cb550_model149/
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