There are three legs of the alternator output (yellow wires). Measuring the AC voltage should give you three voltages. You should use test equipment where you are able to differentiate whether the output is RMS or Peak AC levels.
The RMS AC voltage must be 2 times the peak battery voltage plus 1.4V (to forward bias the 2 diodes) in order to create positive flow into the battery. Peak battery voltage desired is 14.5 VDC Times 2 = 29V. Add 1.4V and you get 30.4v AC RMS. This voltage will be higher when the alternator is not under full load, but must be no lower when it is under full load. *Peak* AC voltages should measure around 30% higher. I would check this voltage with a known fully charged battery.
Both the load and RPM will effect the alternator output voltage readings. The AC readings may be much higher when the alternator in NOT under load.
The charging speed is listed as 1000-9000 RPM in the Honda Manual, with the rated output being at 5000RPM (200 watts, or 12V@ 16.67 amps).
Be aware I have not had occasion to measure the AC voltages of an SOHC4 alternator. What is written here is based on my understanding of circuit theory and physics.
Cheers,
