1982 Honda CB900F Barn Find - Episode 9 - Charging issue

The CB900F isn't charging the battery. Im trying to decipher what it is Rotor, Stator or Reg Rec ?
UPDATE: New Rotor on the way, ill try that first before buying more stuff, it clearly hurt of spec according to folks that know these bikes best. Seems the Stator should be OK, Reg Reg "may" be ok too, we will see.

[@cassiofreitas8559]

You probably have something on the harness draining more from the charging system (a fuse/wire/bad ground that became more resistive). I would start checking the ground points around the bike to be sure they are clean without any rust. If I was a gambler I would bet it’s the rotor, the 4.9 is too low

[@true-moto-resto]

It’s the rotor I think. It measures 2.6 ohms and it should be 3.6 to 4.x New rotor is on the way

[@johnb5519]

That rotor is a weird setup compared to most other stators.

[@true-moto-resto]

Yea, I think all the CB750/900/1100's have that style, but yes, different to most bikes ive taken apart before that typically have a "flywheel"

[@joshua7085]

Did you have any issues with getting the rotor off ? My 1982 Honda cb900c had the original alternator rotor on it, it’s a pain to get off I bought the tool but it broke the tool , any advice would be greatly helpful.

[@true-moto-resto]

I used the rotor puller threaded tool and an impact gun, worked like a charm for me. It’s In one of the videos. I greased the threads on the tool, worked well

[@melchiro79cbx]

Try testing the stator a different easier way. First place your multimeter in the "Tone" setting where it beeps when you have Continuity. Using this setting, check that all three YELLOW wires "Tone out". All three yellow wires should have continuity between each other. Next check to verify that NONE of the three yellow wires have continuity to the stator cover. If any of the above fails, the stator is bad.

[@true-moto-resto]

Thanks, new rotor arrived today (it was bad for sure). Will see how that goes and then a new Reg rev. Stator last if all wiring grounds check ok

[@kumailsyed6401]

Keep us posted

[@true-moto-resto]

Yep, will do

[@yolacmusic4456]

how old is your battery? ,

[@true-moto-resto]

Battery is about 1 week old. its good. Im told by those that know these bikes better than me that the Rotor is definitely bad. Im told the Stator is likely fine and not too far out of range and the reg/reg may be ok. So I have a new rotor on the way

[@user-zu7wd3yq2r]

Wish I could help but I don’t have any idea what any of that means!!! I just watch because of the shiny stuff. LOL

[@true-moto-resto]

LOL, I like the shiny stuff too Don

[@raykirchdorfer5452]

Seams that all your reading are wackey, I would get a better meter, like a fluke, good luck

[@true-moto-resto]

I have a better one, all fixed , bike is finished