SOHC.co.uk Forums > CB500/550
500 four rectifier
Bryanj:
Thats because the 450 doesn't have a regulator, its all done by switching wires in the light switch
AshimotoK0:
Why not use the the regulator from a CB250/350K? It does the same as the Zener on Triumphs but probably a more elegant solution and and acts as a current dump to prevent 'Boiling the battery' as Bryan points in his post. It's a potted unit in an aluminium can with two M6 mount screws.The Triumph had a heatsink and was mounted between forks for air cooling as I remember. I can dig out the circuit diagram tonight if you wish on how to connect the Honda unit, it's 3 wire (Zener is two wire). I have the Genuine Honda Shop manual (paper copy) from 1969 for the CB250/350K0 and it gives a good description on how the single-phase Honda alternator/battery/lighting charge circuit works.
The reulator was made by Hitachi. Thinks its RS-21 model.
Its like This (Any year UK CB250K is the same): -
http://www.ebay.com/itm/Honda-70-73-SL350-CL350-CB350-Voltage-Regulator-RS21-/160451265108
Cheers .. AshD
AshimotoK0:
--- Quote from: AshimotoK0 on March 03, 2014, 08:04:48 AM ---Why not use the the regulator from a CB250/350K? It does the same as the Zener on Triumphs but probably a more elegant solution and and acts as a current dump to prevent 'Boiling the battery' as Bryan points in his post. It's a potted unit in an aluminium can with two M6 mount screws.The Triumph had a heatsink and was mounted between forks for air cooling as I remember. I can dig out the circuit diagram tonight if you wish on how to connect the Honda unit, it's 3 wire (Zener is two wire). I have the Genuine Honda Shop manual (paper copy) from 1969 for the CB250/350K0 and it gives a good description on how the single-phase Honda alternator/battery/lighting charge circuit works.
The regulator was made by Hitachi. Thinks its RS-21 model.
Its like This (Any year UK CB250K is the same): -
http://www.ebay.com/itm/Honda-70-73-SL350-CL350-CB350-Voltage-Regulator-RS21-/160451265108
Cheers .. AshD
--- End quote ---
Checked the '69 250/350 manual.
There are six windings on the field coil of the single phase alternator. Two are connected in a series arrangement used for daytime charging and after full wave rectification the +v side is fed into the regulator.
Please see:. http://www.globalmoto.com.br/imageseletrica/honda-cb250-cb350.jpg
Also looking at this seems the '66 CB450 twin 'Black Bomber' did not have this type of regulator but gained one in '68
http://www.hondatwins.net/forums/57-electrical-discussion/5976-1966-cb450-ko-wiring-problem.html
Cheers.... AshD
AshimotoK0:
--- Quote from: AshimotoK0 on March 03, 2014, 09:15:05 PM ---
--- Quote from: AshimotoK0 on March 03, 2014, 08:04:48 AM ---Why not use the the regulator from a CB250/350K? It does the same as the Zener on Triumphs but probably a more elegant solution and and acts as a current dump to prevent 'Boiling the battery' as Bryan points in his post. It's a potted unit in an aluminium can with two M6 mount screws.The Triumph had a heatsink and was mounted between forks for air cooling as I remember. I can dig out the circuit diagram tonight if you wish on how to connect the Honda unit, it's 3 wire (Zener is two wire). I have the Genuine Honda Shop manual (paper copy) from 1969 for the CB250/350K0 and it gives a good description on how the single-phase Honda alternator/battery/lighting charge circuit works.
The regulator was made by Hitachi. Thinks its RS-21 model.
Its like This (Any year UK CB250K is the same): -
http://www.ebay.com/itm/Honda-70-73-SL350-CL350-CB350-Voltage-Regulator-RS21-/160451265108
Cheers .. AshD
--- End quote ---
Checked the '69 250/350 manual.
There are six windings on the field coil of the single phase alternator. Two are connected in a series arrangement used for daytime charging and after full wave rectification the +v side is fed into the regulator.
Please see:. http://www.globalmoto.com.br/imageseletrica/honda-cb250-cb350.jpg
Also looking at this seems the '66 CB450 twin 'Black Bomber' did not have this type of regulator but gained one in '68
http://www.hondatwins.net/forums/57-electrical-discussion/5976-1966-cb450-ko-wiring-problem.html
Cheers.... AshD
--- End quote ---
Checking the CB250/350K0 1969 parts book I have (a Godsend!!) the regulator is describes as REGULATOR,pointless and has Honda P/N 31400-292-670
The middle Number 292 denotes CB450K1/K2 so it sounds like the part was developed for the later CB450 and used on the CB250/350K !!
http://www.vsource.org/VFR-RVF_files/BHondaPCNs.htm
http://www.ebay.co.uk/itm/HONDA-REGULATOR-31400-292-670-CB500T-CB200-CB350-CB175-CB450-CB360-CJ360-CL175-/290973244434
Cheers.... AshD
Lobo:
Hi Mjc,
Just to clarify the basics as it might help explain.... and Brian / Ash, set me straight if wrong. Whilst I fiddle with electrics on my bikes, cars, boat, Mrs Lobo's kitchen stuff (which is never allowed to die) ... & er, a fishpond .... I cannot lay claim to your Honda / motorcycle experience / backgrounds.
First up, the original question to this thread was could you use a CB500 RECTIFIER, and I maintain 'yes'... just using 2/3 of its branches, ie I basically stand by my wiring diagram on p1 in this respect - whether you do / don't modify the headlamp wiring. (& I'd be temped to if you ride with lights on 24/7 as less dependant upon the headlamp switch / handlebar loom to be in tip-top shape.... assuming you fit a rectifier)
Moving on.. and forgive me for simplifying in parts..
In terms of voltage regulation your 'older' Honda has a different type generator, ie it uses a spinning permanent magnet to energise the stator field, versus an 'electro-magnet' used on later CB bikes. The big, and elegant difference with the latter, is that you can control the 'electro-magnet' (called field coil) by varying the electrical power to it, eg less power in and the field coil become less 'powerful' in the magnetic sense, in turn exciting the stator windings less & thereby causing the generator output voltage to drop. Elegant...why?...because there is no wastage in the system, ie you basically produce what you need. So, how do you vary the input to the field coil?.... it's done via the Voltage regulator which senses loom voltage, and when approximately at 14.5VDC says "Ey up, enough!"... and switches an internal set of points to lessen its electrical output (using an internal resistor) to the field coil.
Now, your older CB has a permanent magnet generator (PMG), ie the above field coil does not exist, rather it only has a rotating magnet of constant strength. Problem for Honda here is choosing 'what's the best strength' - a difficult task given the range of engine rpm and electrical loads the bike will encounter. A compromise can only result, because at low RPM / heavy loads the generator likely won't produce enough power, whereas at high RPM it'd happily boil the battery. (To help minimise the compromise further the wiring design incorporated two available outputs from the generator, ie by switching in an extra winding at headlamp switch ON)
Back to your PMG.... stator winding output is in proportion to engine RPM,... no ifs or buts. So, if it's electrical output is too high (eg high rpm riding) how do you control it.... well, by using the battery on electrically simple bikes (which ain't optimum to say the least).... or by putting a Zener diode downstream of the rectifier; ie between the rectifier & battery. The Zener works by only allowing current to pass upto a certain voltage... and then 'caps' it at that. Elegant.... nope; all surplus power is transformed into heat, which is then soaked away to a large air-cooled heat exchanger. And worse, this is power that in the more modern set up, would have gone to your back wheel...
Ash suggests an alternative, more modern 'pointless' regulator; this type senses loom voltage, and at excess simply shorts a generator stator coil to earth. Elegant ... well better, but not best, as in doing so makes the generator harder to spin (as in how idle rpm drops with lights on?); again robbing your back wheel of useful power.
Bottom line, voltage regulators designed for later field coil set-ups are different animals to the earlier PMG offerings. They do the same job in terms of regulating voltage, ie have the same name, but work in a very different way.
From what I read the Zener type set-up is more agricultural / less reliable & likely harder to install versus Ash's suggestion.
Cheers,
Simon
1st pictorial of what a PMG setup would basically be (red magnet) & 2nd what a field coil setup woul look like.
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