Author Topic: Radioshack rectifier wiring help  (Read 5251 times)

0 Members and 1 Guest are viewing this topic.

Offline dj4sin

  • Full Member
  • *
  • Posts: 11
Radioshack rectifier wiring help
« on: July 10, 2011, 03:01:15 pm »
I'm trying to wire a 1972 cb750 and it's proving to be more of a task than I expected. Just when I think I have an idea of where everything should be connected, I stumble across another thread that seems a little different. My main question is around the two rectifier setup. I'm using the below diagram, but as soon as I connect the wires to the positive battery terminal, they get hot, smoke and potentially melt. Is there something I'm missing ?

Offline dj4sin

  • Full Member
  • *
  • Posts: 11
Re: Radioshack rectifier wiring help
« Reply #1 on: July 11, 2011, 02:27:56 pm »
Any ideas ? Anyone around the Olathe KS area that might want to come help out  :) ?

bollingball

  • Guest
Re: Radioshack rectifier wiring help
« Reply #2 on: July 11, 2011, 02:58:59 pm »
Why not use one (stock) rectifier? Or did 72 750s come with two? Or am I missing something?

                           Ken

Offline camelman

  • Man... Myth... Legend
  • Master
  • *****
  • Posts: 1,899
Re: Radioshack rectifier wiring help
« Reply #3 on: July 11, 2011, 03:12:32 pm »
One of those aftermarket radio shack units should be fine. They are rated for 20 amps or more. That's over 200 watts!
1972 350f rider: sold
1972 350f/466f cafe: for sale
1977 CB400f cafe:sold
1975 CB400f rider: sold
1970 CB750 K0 complete bike: sold
2005 Triumph Sprint ST 1050 rider

We've got to cut it off... and then come down on rockets.  (quoted from: seven minutes of terror)

Offline johnrdupree

  • Enthusiast
  • **
  • Posts: 244
Re: Radioshack rectifier wiring help
« Reply #4 on: July 11, 2011, 03:16:25 pm »
You get smoke just hooking it to a battery?  With the key off?  Sounds like a short.
I did a little googling for 3 phase full wave rectifiers, which is what you're trying to build, and all of them use three of the bridge rectifiers, one for each phase.  From here: http://en.wikipedia.org/wiki/Diode_bridge


The three thick cables from the upper left are the three phases from whatever is generating the electricity (in this particlular case, a wind turbine).  All the negative DC comes off the top and all the positive off the bottom.  And the three bridge rectifiers are attached to a whopping big heat sink.  This makes me wonder if the diagram you're using is wrong.

I'm no expert, so hopefully one will chime in.

Good luck,
~john
1975 Honda CB550K1
1991 Honda ST1100
1989 Suzuki GS500E
1954 NSU Lambretta 125 (long term project)

Offline TwoTired

  • Really Old Timer ...
  • *******
  • Posts: 21,805
Re: Radioshack rectifier wiring help
« Reply #5 on: July 11, 2011, 04:44:09 pm »
You can leave the 2nd yellow connected to just one of the rectifiers.  So you only use half the second rectifier.  It's not critical,though.

The "I" on the regulator terminal is sometimes an idiot light output rather than ignition input.  Depends on the regulator.
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline Pinhead

  • Master
  • *****
  • Posts: 1,818
  • 1979 CB652-ST
Re: Radioshack rectifier wiring help
« Reply #6 on: July 11, 2011, 05:39:50 pm »
I drew that diagram and authored the mod... And am in Shawnee, just north of you!

Send me a PM and maybe I can come give you a hand.
Doug

Click --> Cheap Regulator/Rectifier for any of Honda's 3-phase charging systems (all SOHC4's).

GM HEI Ignition Conversion

Quote from: TwoTired
By the way, I'm going for the tinfoil pants...so they can't read my private thoughts.
:D

Offline camelman

  • Man... Myth... Legend
  • Master
  • *****
  • Posts: 1,899
Re: Radioshack rectifier wiring help
« Reply #7 on: July 11, 2011, 06:10:22 pm »
Try this link. The diagram lays out which color wires to which post. You only need one of those regulators. http://www.hondatwins.net/forum/viewtopic.php?f=53&t=7933

Camelman
1972 350f rider: sold
1972 350f/466f cafe: for sale
1977 CB400f cafe:sold
1975 CB400f rider: sold
1970 CB750 K0 complete bike: sold
2005 Triumph Sprint ST 1050 rider

We've got to cut it off... and then come down on rockets.  (quoted from: seven minutes of terror)

Offline johnrdupree

  • Enthusiast
  • **
  • Posts: 244
Re: Radioshack rectifier wiring help
« Reply #8 on: July 11, 2011, 06:19:16 pm »
I drew that diagram and authored the mod... And am in Shawnee, just north of you!

Send me a PM and maybe I can come give you a hand.

Hey, look at that!  An expert.  I knew one would come by soon enough.
1975 Honda CB550K1
1991 Honda ST1100
1989 Suzuki GS500E
1954 NSU Lambretta 125 (long term project)

Offline Pinhead

  • Master
  • *****
  • Posts: 1,818
  • 1979 CB652-ST
Re: Radioshack rectifier wiring help
« Reply #9 on: July 11, 2011, 06:44:01 pm »
I drew that diagram and authored the mod... And am in Shawnee, just north of you!

Send me a PM and maybe I can come give you a hand.

Hey, look at that!  An expert.  I knew one would come by soon enough.

Yeah, TwoTired posted before I did. ;)
Doug

Click --> Cheap Regulator/Rectifier for any of Honda's 3-phase charging systems (all SOHC4's).

GM HEI Ignition Conversion

Quote from: TwoTired
By the way, I'm going for the tinfoil pants...so they can't read my private thoughts.
:D

Offline dj4sin

  • Full Member
  • *
  • Posts: 11
Re: Radioshack rectifier wiring help
« Reply #10 on: July 11, 2011, 08:15:58 pm »
Pinhead, that would be awesome if I could get someone to come give me some pointers. I really want to enjoy this bike and the learning process, but it is getting to be a little overwhelming. I'll definitely give you a PM sometime tomorrow. Thanks again.

Offline scottly

  • Really Old Timer ...
  • *******
  • Posts: 15,647
  • Humboldt, AZ
Re: Radioshack rectifier wiring help
« Reply #11 on: July 11, 2011, 09:39:22 pm »
My main question is around the two rectifier setup. I'm using the below diagram, but as soon as I connect the wires to the positive battery terminal, they get hot, smoke and potentially melt. Is there something I'm missing ?
The easiest way to let the smoke out of a rectifier is to hook it up backwards. The + terminals on the rects have to be connected to battery plus, and the - terminals are connected to ground. Did you mistake the + symbols on the rect in the pic for - symbols?
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline camelman

  • Man... Myth... Legend
  • Master
  • *****
  • Posts: 1,899
Re: Radioshack rectifier wiring help
« Reply #12 on: July 11, 2011, 10:16:16 pm »
Pinhead, that would be awesome if I could get someone to come give me some pointers. I really want to enjoy this bike and the learning process, but it is getting to be a little overwhelming. I'll definitely give you a PM sometime tomorrow. Thanks again.

Take a look at the pic in the link I posted.  Just crimp on new ends for the wires and hook it up.  It really is just that simple and you can do it yourself in about twenty minutes.  If only everything on these bikes was that simple...

Camelman
1972 350f rider: sold
1972 350f/466f cafe: for sale
1977 CB400f cafe:sold
1975 CB400f rider: sold
1970 CB750 K0 complete bike: sold
2005 Triumph Sprint ST 1050 rider

We've got to cut it off... and then come down on rockets.  (quoted from: seven minutes of terror)

Offline scottly

  • Really Old Timer ...
  • *******
  • Posts: 15,647
  • Humboldt, AZ
Re: Radioshack rectifier wiring help
« Reply #13 on: July 11, 2011, 10:19:18 pm »
C-man, that link is for a single phase twin, not a 3 phase system like the sohc4s. ;)
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline camelman

  • Man... Myth... Legend
  • Master
  • *****
  • Posts: 1,899
Re: Radioshack rectifier wiring help
« Reply #14 on: July 11, 2011, 10:34:20 pm »
C-man, that link is for a single phase twin, not a 3 phase system like the sohc4s. ;)
Shizen-poopa.  Well, never mind anything I wrote.  I never even looked at the wiring harness coming out of the alternator on the twins I did that conversion on.  I just figured they all had the same setup.  For what it's worth, it works great on CB350 and CB405 twins.  ;-)
1972 350f rider: sold
1972 350f/466f cafe: for sale
1977 CB400f cafe:sold
1975 CB400f rider: sold
1970 CB750 K0 complete bike: sold
2005 Triumph Sprint ST 1050 rider

We've got to cut it off... and then come down on rockets.  (quoted from: seven minutes of terror)

Offline dj4sin

  • Full Member
  • *
  • Posts: 11
Re: Radioshack rectifier wiring help
« Reply #15 on: July 12, 2011, 07:32:02 am »
I sent you a PM Pinhead.