Topic: CB500 and CB550 carb spec guide

[Flyin900]

I am looking for the model guide that has all the different carbs used from the early CB500K0's to the last CB550's in 1978. Someone on here I think it was Deltarider had a link to this information.
I cannot seem to find the link again or any direct info posted in the tech sections on the site. Any direction to the info and link would be greatly appreciated.

[Deltarider]

This is the one I've put together, but it is limited to the oldstyle carbs.
* Until proven otherwise, we think it is safe to assume the 627B carb bodies (venturis) are identical to the 649A. The models with the 627B carbs had #100 main jets and lacked the air duct over the airfilter. Slow jet is also #40. Models for the UK and France had the jet needle - like the 649A - in middle (3rd) position and also - like the 649A - had a recommended airscrew position of 1 turn out +/- 1/8. According to a specifications booklet edited in 1977 (!) by American Honda Motor Co., Inc., the CB500s overthere had the jet needle's clip in 4th position and a recommended airscrew position of two turns out. Maybe US was particularly interested in reducing emissions at idle.

[Deltarider]

But there are others that I cannot take responsibility for.

[Deltarider]

Note that the Shop Manual Honda CB500 - CB550 has an error on p.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 CB550(K) carbs to CB550F carbs - also... no CB500 models ever had the 022A carbs.
* One mystery remains to be resolved: the airscrews on the 087A carbs that were on the CB550K2. Why is it that the particular parts list on p. C10 suggests the 087A had the same (solid) airscrew (16016-390-004) the F models had in their 069A carb? So far no owners of a K2 reported they actually have them. Instead they have the same crossdrilled (16016-323-004) airscrews the previous K models had. p.C10 in: http://www.honda4fun.com/pdf_parts_list/pdf_spac550/CB550-K0-K1-K2/CB550-K0-K1-K2_04.pdf

[Flyin900]

Delta, Thank you for the reprint of this info and I have saved it this time in my files for future reference.

Here is what I am dealing with on this project. A 1972 CB500 K1 frame and mostly complete general mechanicals from this 1972 bike. The motor is a CB550E - 2012433 serial number and the carbs on this motor are 627B carbs with 100 main jets and 40 secondary jets. From what I can tell the carbs are then from the 1972 CB500 motor and not correct for the CB550 motor that I have in this frame.

I am not clear on what year the CB550 motor is from since I cannot seem to find a production year reference on the motor serial number #2012422. From my limited knowledge, I believe this is a later 1977 or 1978 year motor as a best guess and would appreciate some clarification.

I do have access to a set of PD46A carbs which I rebuilt for someone who conversely was going to put them on his CB500 project motor. So I have spoken with him and a swap is possible, if it makes sense to put the 627B's on his CB500 motor and the PD46A's on my later CB550 motor.

Any insight and clarification would be greatly appreciated on the above information and proposal.

[RAFster122s]

Pull the breather cover on your 550 motor. If there are 4 nuts the motor is from 74-76, unless the cover is not original (typically not the case on most motors unless they have clear evidence of being apart...).  The 77-78 motors have 8 nuts beneath the breather cover, four of which pin the rocker shafts.
Hope this is helpful