Topic: CB750K4 - new updates 21 Apr 2025 - autopsy -non-charging bike

[scottly]

Yeah, it should be zero, or very close to zero. Try measuring the voltage of the old battery.

[andy750]

new battery: meter still reads 40 ohms across leads. Touching leads together still gives a reading. Maybe time for a new meter - any recommendations on which one to get?

[scottly]

There may be a problem with the meter leads themselves. Try removing one lead at a time from the meter and measuring with the remaining lead to the meter socket.

[andy750]

Ok here is the current state of the K4:

K4 was retrofitted years ago with Anders Upgrade Alternator and it has worked great. In October of last year I noticed battery was not charging and it was either the stator (Yamaha R6 2006-2008 stator) or the regulator/rectifier (also Yamaha R6).

I have removed the reg/recitfier and have a replacement to test. I want to do the same with the stator but not sure how to go about that as the stator looks like it has the wires spliced to fit into the K4 format. Anyone with Anders upgrade know what to do here to remove/replace the stator? First Ill rewatch the video above about testing stators to refresh my memory 

Thanks
Andy

[andy750]

Regulator/rectifier

[scottly]

The three stator wires go to the rectifier side of the reg/rect; it doesn't matter which one goes where. Not sure what you mean by "spliced to fit into the K4 format"?

[scottly]

What does the wiring look like on the new stator? Does it have the rectifier plug on the end? Also, did you get a good meter yet?

[newday777]

The three stator wires go to the rectifier side of the reg/rect; it doesn't matter which one goes where. Not sure what you mean by "spliced to fit into the K4 format"?

As in the three yellow wires from the stator connecting(spliced as Andy wrote) into the three yellow wires of the K4 harness. Right Andy?
So Andy, you can connect any yellow stator wires to any one of the bike harness yellow wires, it doesn't matter which yellow gets connected to any one yellow to yellow combination. (My brain didn't put together that you meant the stator had yellow wires too when you asked a couple weeks ago!)

[scottly]

The three wires go to the R6 rectifier plug, not the Honda harness, from what I can see. Perhaps the wires were cut to feed them through the rubber block that seals the opening in the Honda cover, then spliced back together?

[newday777]

I haven't seen it in person Scott either.

[HondaMan]

Splicing those wires is a good idea: the little OEM bullets connectors are only good to 13 amps, over which they quickly burn.
I'd certainly do that if I had one of those fireball alternators. It would be real nice to have 30 amps on tap!

[andy750]

Thanks for the replies and sorry I wasn’t more clear. You can see in the photo below the R6 stator plug and the OEM white plug connector come out of the same sleeve. I plugged the white OEM connector in for reference. So if I replace the stator what do I do with the OEM plug? Do I need to re-sleeve it with the new stator?

And what is the blue/red wire you see in the photo? Is that going into the OEM connector?? What’s it for?














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[andy750]

Scottly I did get a new multimeter (borrowed from neighbour) and the stator read 0.5 Ohm when connected 1-2, 2-3, 1-3. Continuity gave a reading on 2/3 pins which I guess means stator is shot.

[newday777]

Need more clarification Andy.
Are these pictures showing how it was wired by Anders?
If so, where is the regulator/Rectifier plug in?

[andy750]

Need more clarification Andy.
Are these pictures showing how it was wired by Anders?
If sh where is the regulator/Rectifier plug in?

Yes this is the setup from Anders. The regulator/rectifier plugs into the plug circled in red and OEM plug that comes from same sleeve as stator also labelled. Let me know if that helps...

[newday777]

Anders explained it to me 4-5 years ago but I didn't see a wiring diagram when he explained it and I didn't get the setup as I couldn't afford it then so I haven't seen it in person how it should be. Did you get a wiring diagram for it from him?

[andy750]

Anders explained it to me 4-5 years ago but I didn't see a wiring diagram when he explained it and I didn't get the setup as I couldn't afford it then so I haven't seen it in person how it should be. Did you get a wiring diagram for it from him?

No wiring diagram just the finished product which is why I was hoping someone on here who has done it themselves may be able to help. Looks like i need to replace the stator and so i would like to know what to do with the OEM plug/blue-red wire.

I emailed Anders for help...

Thanks anyway!
Andy

[newday777]

Wiring diagram shows blue/red as oil pressure feed

[MRieck]

I have the unit on my bike Andy but I'm in MA until later this week and the bike is in NH. I used used OEM type block connectors for my stator wires and yes...you have to reuse the rubber block though new ones are now available. Your stator wires look burnt at the connections. It would be a good idea to replace those OEM type connectors and use fresh wire too.
 I can't remember seeing modern rec/regs going bad (except on my busa  ) It has always been the stator. I replaced quite a few on the old Kawasaki Vulcans

[MRieck]

Splicing those wires is a good idea: the little OEM bullets connectors are only good to 13 amps, over which they quickly burn.
I'd certainly do that if I had one of those fireball alternators. It would be real nice to have 30 amps on tap!

It is awesome. Another notable benefit is the large number of longer rollers that grab the starter gear when starting the bike. Between keeping the battery fully charged and eliminating the coil draw the engines turns overs fast no matter what compression.

[andy750]

Wiring diagram shows blue/red as oil pressure feed

Thanks Stu!

[andy750]

I have the unit on my bike Andy but I'm in MA until later this week and the bike is in NH. I used used OEM type block connectors for my stator wires and yes...you have to reuse the rubber block though new ones are now available. Your stator wires look burnt at the connections. It would be a good idea to replace those OEM type connectors and use fresh wire too.
 I can't remember seeing modern rec/regs going bad (except on my busa  ) It has always been the stator. I replaced quite a few on the old Kawasaki Vulcans

Thanks Mike! Ill order another stator and remove current one. If I still have issues Ill come and see yours

[newday777]

Wiring diagram shows blue/red as oil pressure feed

Thanks Stu!

Was it hooked up and working?

[andy750]

I ordered the new Stator & Field Coil Wire Exit Rubbers from Cycle X

[andy750]

Wiring diagram shows blue/red as oil pressure feed

Thanks Stu!

Was it hooked up and working?

Yes hooked up and I think this is what is going through the OEM white connector shown in the photos. So if I replace the stator I have to figure out how to deal with this wirde - prob just run it separately. I found this photo of the upgrade kit in the Alternator upgrade thread which is helpful.