500 four rectifier

[Woodside]

Hi guys just a quick one.
Does anyone know if a 72 500/4 rectifier 5 wire will work ok on a 72 cb450 twin
Thanks in advance

[Norniron]

Hi guys just a quick one.
Does anyone know if a 72 500/4 rectifier 5 wire will work ok on a 72 cb450 twin
Thanks in advance

Sorry i dont know but if it doesnt sell me the rectifier cos i need one

[LesterPiglet]

Without seeing it I would guess yes. I took one straight of a 750 for my 550.
I used one from a Superdream for a Suzuki GSX 750esd.

[Lobo]

... can't see any issues, its job is to simply convert alternating current from the spinning  generator to a form of 'flat line' direct current (ie regulated) fit for charging the battery. In other words it doesn't care which bike its on...

This said, it you were going to put it on an ocean liner it'd fail as not man enough for those loads.... but your going down a notch slightly & I personally can't see any problems.

....yea, I know.... YAWN!

[Bryanj]

Don't think so as the 450 generator has "switched" coils via the lights on/off switch

[Woodside]

Ok
So rectifying wise it should do the job.....but I'm guessing it being switched via the lights it steps up some to.cope with the extra load...

The 450 it's going on only has front / rear plus brake light.
Other than that it's pretty much for charging the battery so can I illiminate the switched coil?

[Lobo]

Mjc... I really should 'consider' before posting! Have now done a bit of background grubbing on the CB450 and, typically, come across differing wiring diagrams, differing 'informations'.... it all gets so bloody difficult when something's just not in your hands...

It seems your bike has a permanent magnet generator (no generator exciter coil).... and some sources suggest no regulator... as the charging setup just so relatively weak. Dunno, again, Brian / any older CB riders (ie the bikes, not the individuals!) might be better qualified to help.

But, here goes my take on it. 

Brian (as always) is correct that headlamp switching is involved... one source of info I read / wiring diagram says the switch 'simply' provides / connects one 'raw AC' winding up to the lights - ie the lights run on 12v AC. (seems unlikely I'd have thought). And yet another diagram / words of wisdom suggest that the generator normally supplies 2/3 power, but at lights on adds in another coil to give full power.

My best guess, is the latter, with the white & yellow (generator) wires being connected at lights ON. From the 'best' wiring diagrams I can find I'd suggest you directly connect the white / yellow loom wires within the headlamp bowl (tape the switch connections up)... and then connect the pink / yellow wires from the generator to any 2 Yellows of your CB500 rectifier.  And then, if you have a voltmeter, confirm charging voltage all in limits.

Sorry can't be of more help,
Simon

[Woodside]

Cheers Simon
When you say "sorry I wasn't any more help". Are you kidding?   Other than coming and wiring it up for me that's great......and that's not a hint....
I guess I should have said up top that I have no loom and all wiring is to be made from scratch.   
But thanks again that's fantastic


Best tool in the box this week "sohc forum"

[Lobo]

You're welcome, but sorry... no guarantees. Much written on CB450 forums, the electrical system does not seem particularly, er, robust! Read one alarming bit where the electrics failed and fault eventually traced to the tacho cable being disconnected.... this was the handlebars 'Earth' since the steering head bearings were failing to pass current! Anyways, will be interested to hear how it pans out.

Btw, have you a voltage regulator in the system?

Oh, and please... anyone out there have better / hands-on knowledge of old CBs & this topic speak up, I'm no guru & working a bit blind from Google bits'n'bobs.

Cheers again,
Simon

[Woodside]

Hi simon
Thanks again
I reckon I can sort this now.....
I only need it to charge the battery so it will keep the starter happy.....
I will be fitting lights maybe sometime....I can't load a picture at the moment of the project but I will try again soon....
It has no wiring as we speak so its all abit of a work in progress .....arnt they all???

[Bryanj]

If you wire it up permanently fully charging, any time you run with the lights off you will boil the battery and any time with the lights on it don't quite charge enough , Tucked if you do and same if you don't!!!!

Only answer is emulate a 70's Triumph and fit a well cooled, high amp Zener diode

[Lobo]

Yup Mjc, Bryan has a point which is why I asked in the last post "do you have a voltage regulator in the system?"

If not, can I suggest you leave the headlamp wiring as Honda designed..

If yes, then wire as the sketch... or Bryan's suggestion. (a Zener diode only allows a certain voltage to flow... think I saw your generator is capable of 110W implying you'd need a 10A Zener minimum)

With electric start, congested / slow roads and our tendency to drive with lights on 24/7 I'd be reckoning to wire it in the 'full charge ahead' option!

On a couple of wiring diagrams I saw there was no regulator... leaving me to think the perm magnetic generator is pretty 'weak' and the regulation left to the battery in the system. This too would explain the supplemental winding for 'lights on'.

But... I've also seen CB450 wiring diags showing a regulator. So, confused.

Anyways, enjoy the fiddling...
Simon.

[Woodside]

Ok
I found this in my box of treasure?

Perhaps it will do the job

[Bryanj]

Nope, thats for a gereator with a wound field coil (400,500,550,750). Yours is a permanent magnet rotor. The only thing that will work properly is the correctly wired original type switches or wire it all permanently charging and use a zener.

You seem to be intent on going your own way and not listening mate

[Woodside]

No Bryan
I am listening I honestlythought that was it....

Thanks for putting me right. 

I'll be looking into a zener diode this week then. The only reason I have not yet is because I was certain I had a regulator somewhere but I was not aware it was the wrong one....

Or indeed no good what so ever
And once again I appreciate all the help