...OK, now that I have your attention:
The low output of the CB500/550 alternator comes largely from the poor construction of the rotor. You only need to look at its bigger brother SOHC4 rotors to understand it: the early 750 (290 watts output, MAYBE) had poor welds in the 'holes' of the rotor, while the F1 and later versions (330-350 watts output) were very clean, machine-welded (instead of hand-welded) rotors, with half as many welds and occasional grinding marks showing where they were balanced. The later ones make more power, probably spurred on by the requirements of the CB750A bikes, which had more output power because of both improved rotors and higher-current (i.e., stronger magnetic field) of the "A" field coil. The "A" has a solid-state regulator, but this is not the source of the increased output: it is merely the throttle thru which the battery voltage is maintained.
When looking at the 500/550 version, one can barely even SEE the field coil, and this means that many fewer magnetic lines make it out of the coil to be 'chopped' by the holes-and-steel of the rotor to make the alternating field. The welds always look gloppy and amateurish, and from my experience in other Honda areas of the time, I know to have been built by the lowest bidder, and with somewhat less QC in the process. Honda was deeply in debt in other development areas (like the early GL1000 prototypes, which started in 1974) as they also were converting to CNC machines to replace their early NC versions, so low cost parts were the order of the day. (That cool Honda movie someone posted here has reminded me of these things...)
My plan, if I can secure the 2 most-required portions of this, is to (1) test an "opened" (and somewhat lighter) rotor, which will be hand-cut by yours truly to attain what I want, against a standard rotor on the CB550 that is the topic in my next book (underway). The 2nd 'item' I need to find is a (high-speed) spin-balancer service to repair what I will do to the balance in the process, which appears to be personna non grata in the Denver area. The final goal is to improve the alternator output substantially without having to resort to solid-state regulators, for which these alternators were not designed. Those devices can raise the battery voltage in some cases, but at the cost of higher the field wiring temperatures - this disturbs my conservative engineering nature, especially on aged equipment.
So, my requests for forum help for this project is:
1.) Does anyone have a rotor they would be willing to part with? It probably won't be returning home in the end, but will end up on my 'project' bike.
2.) Does anyone know a good spin-balancer in their area who can undertake to spin-balance this part to 11,000 RPM?
