This is true for the K0 to K4. In 1972 Hm upgraded the rectifier from a seliumn bridge to one that used silicon based diodes. Silicon diodes are more efficenct. From the K5 and on the bike's came with a 35/50w headlight. I'm running a 45/45w H4 in my K5. I don't ride this bike at night.How much power do they draw? The CB450's charging system barely makes enough power to operate the 35W high beam above 3000rpm; below that, and it will start to discharge. The low beam is 25W, and will make the charging system just about break even when just above idle.
Cool! So if I focus on the stator, rotor, and rectifier of a K5 to K7 I should be able to run a 35W projector beam with no issues :ugeek:They must have rewound the stator as well - I have a series-pass regulator, and it charges about the same as the selenium; perhaps a bit better, but not enough to run a 50W lamp, even with LEDs everywhere else. I installed a 30W LED headlamp, which is so much brighter than the filament that I can ride at night - I usually don't, though.
Interesting; I just checked my parts book, and it shows the same rectifier in the K5 as the K3 and K4. Maybe it was updated after my data was released. It does show a different part number for the K5 stator, though.
Seems like it. It still may not keep up if you let it idle a long time, but if you install a Voltage monitor, you can avoid that by revving a bit if it drops off.Cool! So if I focus on the stator, rotor, and rectifier of a K5 to K7 I should be able to run a 35W projector beam with no issues :ugeek:
My understanding is the stator is the same for all 5sp models. The rectifier changed on the K5 (see www.cmsnl.com CB450K5 USA). All of the large headlight CB450 were equipped with 35/50w healights from the factory (see cmsnl.com CB450K5 and the FSM wiring diagram for K7). The Silcon rectifier was more efficent than the older selinum, or less current loss. My bike is fine with th 45/45w headlight. I have LED tail light and LED dash lights. This give me about 12w back over stock lights. Also the bike has a new harness with all 12GA wire. I want to try a 55/60w H4 next summer to see what happens. The bike does have a voltage meter i can monitor while riding.Cool! So if I focus on the stator, rotor, and rectifier of a K5 to K7 I should be able to run a 35W projector beam with no issues :ugeek:
Wintrsol,Interesting - my parts list shows only the rotor and stator changed with the CB450K5, and not the rectifier. The K3/K4 rotor is 31101-292-003, while the K5 rotor is 31101-346-670, and the K3/K4 stator is 31102-292-013 and K5 stator is 31102-346-670. These are the part number differences shown at your linked site, too. The rectifier is shown as the same part number on that site (31700-292-008), but listed as superseded by part number 31700-455-671 for all. So, the big change was rotor and stator, not the rectifier, although I'm sure the latter helps.
Wow! I just looked at the price for the generator set - $1325!!!
A good quality silicon rectifier will exhibit ~0.6V drop with any significant amount of current; even a Schottky diode starts in the 0.4V range, increasing with increasing current. Schottky diodes have a lot of reverse leakage, though, so aren't a good choice. So, your calculation of available power increase is a little off.Wintrsol,
It is my understanding all of the 5sp stators were equivelent in terms of electrical output. This is an assumption based on studing the Honda Factory Shop Manual and reading this forum. I agree Honda used different part numbers. Honda changed from Selenium diode rectifiers to Silicon diode rectifiers in the 1972 year. I think this applies to the 350 series too. All diodes Selenium and Silicon exhibit a voltage drop. A Selenium rectifier will have about a 1v drop and a modern Silicon rectifier will have about a .1v drop. At 13v (CB450 operating range for the electrical system) that is about a 12w difference in output.
For the headlight I understand, using a new reflector alone does make it a lot better, keeping the charming filament bulb.Why would you want to change the charming old lights out from these character filled old bikes?