Topic: 1976 Honda CB550 jet needle clip position?

[denward17]

Trying to determine the needle clip position as Honda intended.  I just received a complete set (4 carbs) of the jet needles and emulsion tubes from Honda.

I only have 1 carb needle out so I could inspect.

Old needle I suspect is a Keyster part? D26

New needle has part # 272304 on it.

Just for grins I tried to measure with calipers:
Length:
D26 = 55.55mm
272304 = 55.85mm

Tip diameter:
D26 = 1.39mm
272304 = 1.41mm

This explains why it is a tad rich down low speed operation.

Now what do I do about the clip position?  As it came apart, it was in the 4th position from top, don't know if this is where Honda intended or not, I cannot find a reference.

[bryanj]

In uk all of them were in middle possition or 3rd(from either end)

[denward17]

Thanks Bryan, forgot to mention these are the 087A carbs if that matters.

[bryanj]

Dont think so

[Deltarider]

I'd opt for the 4^th position from top. That was prescribed for the 022A carbs (CB550(K0) and CB550K1) and so far there's no indication whatsoever the 087A carbs were any different in spite of a changed stamped in number. Engine, air intake and exhaust were all identical.
The same needle was in the CB500s where it was in 3rd (middle) position. Makes sense: seen its partnumber (-323-), the needle set had been designed for the CB500.

[jonda500]

Both of my Australian CB500's had original needles (272304) and the needle clips #4 (from the top) when I got them. I have not been able to verify how they came when new here, but I have tried the clips at #3 (middle position) and both bikes run much better with the clips at #4, however my resurrected one has #35 pilots rather than #40 and the air screws at 3/8 turn out from seated.
If we had a poll here, I think #3 would win but I would vote for #4!
John

[Deltarider]

The 16012-323-004 NEEDLE SET, JET made its debut on the CB500 Fours. Standard position on the 500s was 3rd (middle), which makes sense. Some years later the CB550K entered the scene and Honda used the same NEEDLE SET, JET in their carbs: 022A and 087A. All documents I have seen, suggest the position was 4th from top.
When the former carbs 022A, which were on the CB550(K0) and the CB550K1, were renumbered, with the launch of the CB550K2 (aka CB550K76), in 087A, you'd expect something had changed. In the parts list we find only one clue. According to that American Honda document the 087A had the same solid tip airscrew the 069A carbs had which were on the F models (Super Sport). But... none of the respondents I have asked, reported this airscrew in their 087A carbs. They all had the open cross drilled airscrews which were also in the 022A carbs. What else could be there to justify this renumbering  of 022A in 087A?
Changed venturis? Mwah, not likely. What else then? The only thing left I could think of was a maybe different position for the needle clip. But... according to respondents this has not materialized either. They had the clip in 4th position, the same position they were in the 022A carbs. So it seems the 087A carbs were a 100% identical to the 022A carbs, except for that different number stamped in.
 

[denward17]

Installed the new jet needle set today and decided to put clip in 3rd(middle) position.  I will finish install and balance carbs probably Wednesday and see what it does.

Will update later in the week (assuming I get a chance to go ride, monsoon season this week with on/off rain).

[jlh3rd]

from this:
fyi.

[HondaMan]

The 16012-323-004 NEEDLE SET, JET made its debut on the CB500 Fours. Standard position on the 500s was 3rd (middle), which makes sense. Some years later the CB550K entered the scene and Honda used the same NEEDLE SET, JET in their carbs: 022A and 087A. All documents I have seen, suggest the position was 4th from top.
When the former carbs 022A, which were on the CB550(K0) and the CB550K1, were renumbered, with the launch of the CB550K2 (aka CB550K76), in 087A, you'd expect something had changed. In the parts list we find only one clue. According to that American Honda document the 087A had the same solid tip airscrew the 069A carbs had which were on the F models (Super Sport). But... none of the respondents I have asked, reported this airscrew in their 087A carbs. They all had the open cross drilled airscrews which were also in the 022A carbs. What else could be there to justify this renumbering  of 022A in 087A?
Changed venturis? Mwah, not likely. What else then? The only thing left I could think of was a maybe different position for the needle clip. But... according to respondents this has not materialized either. They had the clip in 4th position, the same position they were in the 022A carbs. So it seems the 087A carbs were a 100% identical to the 022A carbs, except for that different number stamped in.
 

The story here is similar to the CB750F3 PD42 carbs: there are 2 suffixes /a and /b, but the carbs seem the same in every respect. In the USA this was merely a bureaucrat's joy as the first version was the /a, but for certain USA cities (Los Angeles, CA, New York, NY, and Chicago, IL) the air-emulsion holes were verified to be a prescribed size to the idle jet and mainjet emulsion tubes. In all that I have cleaned & rebuilt, they are identical for all practical purposes, but the /b versions had to have a 'certificate' of verification before the bikes could be delivered (to the dealers) to be sold in those cities.

[denward17]

Was able to get the carbs synced and went for a short ~23-24 miles today.

Bike is running fantastic!  The low speed gurgle is gone, when I turn into a low speed corner in 2nd gear and slowly increase throttle it is crisp now, no hesitation.

To recap:
I had Keyster D26 needles in the 4th slot, they were removed  and I installed the Honda needles (272304), with the clip in the 3rd (center) position.
These are the 087A carbs.

With old needles I tried to compensate with the air mixture screws and went up to about 2 3/4 turns out, it helped but gurgle was still there.  With new needles I am 1 1/2 turns out.