CM91 Rectifier

[dadspurg]

I just purchased a new Rectifier from Dig-Key for a Bridge Rectifier VS GBPC2504
A 1P 400V 25A GBPC-A. Labeled + - S and S. 4 blade connectors. I have 3 connections on the old rectifier. pink, yellow and power +.
How should i connect the new rectifier?
thanks much.

 

[b52bombardier1]

You have an oddly turned tab on the new Digi-Key rectifier and your red wire will go there. Directly diagonal down and across from the oddly turned tab, you need a newly made ground wire from the battery negative post. Your original selenium rectifier had no ground wire because it grounded through the old rectifier mounting tab.

The yellow and pink wires are the alternating current output wires from the stator and either wire can go to either of the remaining two tabs of the rectifier.

Mount the new silicon rectifier using the empty bolt hole in the middle. The new rectifier case is not grounded but could use a little heat dissipation through the case to the bike frame. Especially if you spend a lot of time at high RPM.

Buy some female spade connectors for your wires and then heat shrink those connections prior to mounting the new rectifier.

Rick

 

[dadspurg]

You have an oddly turned tab on the new Digi-Key rectifier and your red wire will go there. Directly diagonal down and across from the oddly turned tab, you need a newly made ground wire from the battery negative post. Your original selenium rectifier had no ground wire because it grounded through the old rectifier mounting tab.

The yellow and pink wires are the alternating current output wires from the stator and either wire can go to either of the remaining two tabs of the rectifier.

Mount the new silicon rectifier using the empty bolt hole in the middle. The new rectifier case is not grounded but could use a little heat dissipation through the case to the bike frame. Especially if you spend a lot of time at high RPM.

Buy some female spade connectors for your wires and then heat shrink those connections prior to mounting the new rectifier.

Rick

Thanks Rick. That is a huge help. really appreciate it. couple followup questions. 1) So I should NOT isolate the rectifier from the frame by placing a rubber gasket between them, rather butt it up next to the frame to allow heat transfer to the frame. 2) THe battery for this bike has 2 positive leads. One with an inline fuse, the other lead without a fuse. Which should go the the rectifier? (the other connection to the battery appears to be a blue/greenish lead that feeds into the wiring harness under the seat and goes to "I don't know where".) thanks

 

[b52bombardier1]

For me and the many wiring diagrams that I have here - its the wire that does NOT have the fuse that goes to the oddly turned tab on your new rectifier. For most of my bikes, that is a red wire with a white stripe.

I have no idea where a blue green wire would go because I have no CM91 wiring diagram here. There is a certain amount of risk that you are assuming here and I wish that I could be more certain for you.

The case of your new rectifier does not matter electrically here though it could use a little heat dissipation being mounted to the bike frame.

Rick

 

[dadspurg]

Thanks Rick... I think you've given me enough info to get this right. I'll put an ohm meter on the mystery cable and see where it leads.. my guess the headlight area. I appreciate your help on this... wish me luck

 

[dadspurg]

Thanks Rick... I think you've given me enough info to get this right. I'll put an ohm meter on the mystery cable and see where it leads.. my guess the headlight area. I appreciate your help on this... wish me luck

For me and the many wiring diagrams that I have here - its the wire that does NOT have the fuse that goes to the oddly turned tab on your new rectifier. For most of my bikes, that is a red wire with a white stripe.

I have no idea where a blue green wire would go because I have no CM91 wiring diagram here. There is a certain amount of risk that you are assuming here and I wish that I could be more certain for you.

The case of your new rectifier does not matter electrically here though it could use a little heat dissipation being mounted to the bike frame.

Rick

Rick
I found a CM91 wiring diagram. You are correct on the above.
I bought a new ignition/key switch. Of course the wiring colors are different than what is on the bike today.
It describes the 5 wires as HL (headlight?) IG (Ignition?) SE ( do you know?) DY (do you know?) Bat (battery)
can you explain SE and DY? Thanks