Topic: No Charging CB350 70’

[Ringostar1982]

Hello there... 

I have a problem with my brothers CB350 70‘s wiring. I hope anyone have a hint for me.

The bike was slightly rebuilt and get a smaller gel battery (12V 9Ah) installed.
But he stopped at the first ride.Empty battery. I have read that it could happen if the old rectifier is dead.
So I replaced the old rectifier and the voltage regulator with a combi unit. Now I have noticed that there is no correct charging voltage.
The charging voltage is only about 12.5V when idling. With lights on just 11.8V !
At speed about 5000 rpm also only 12.8V max.
 
according to the manual there should be about 14.8 V to load the battery.
 
I did a measurement on the alternator between the common pink wire and the two others.
The values should be 0.55 Ohm and 1.10 Ohm.
I have measured 0.8 Ohm and 1.5 Ohm.
Seems to be ok for me.
 
Attached you can see my wiring.
 
Should I take the white and yellow wire together?
Change yellow and white wire?
Today I will also check if the grounded housing of the rectifier/regulator housing is correct and is in contact with the battery minus.
 
Can you please check…
Thanks!

[Ringostar1982]

So guys I checked all connectors, grounds, tested with direct wires to AC and tested with old rectifier. Always the same. At least I checked the Alternator Voltage in AC Mode between Pink and yellow and got only 14 V at idle and 17.6V at 5000 rpm. That’s to low I mean or?

[kslrr]

I can't recall the proper voltages off hand.  It's been awhile since I've worked on mine.

Do you have the service manual to reference?  If not, go here http://forums.sohc4.net/index.php/topic,17788.300.html
to download what you need.

[Ringostar1982]

Hey... yes i do. But there are just the DC Values inside of the rectifier.
12.5V x sqrt 2=17.6V and that’s what I should have at idle.
14.8V x sqrt 2= 20.9V for about 5000rpm
 ???if iam right.

[kslrr]

Why are you converting the listed values of 12.5 and 14.8 to 17.6 and 20.9?

[Ringostar1982]

I mean the AC-> DC conversion

17.6V AC from stator coil  /  sqrt 2=12.5V DC Output of the rectifier.

But I-am still not sure about that factor.
I will dismount the stator and have a look to it maybe I can see something wrong. 

[Ringostar1982]

ok. there are some news.  I did the measurement at the stator wires again. This time with all wires open circuit! my mistake.  So now i got about 55 to 60 Volts AC from the coils -> Alternator should be ok...
 Then i did the white/yellow Mod to see how much voltage i can get!
 Checked again the Output Voltage with the old Rectifier/regulator mounted -> maximum 13.3 VDC and with the new combination unit there is a constant value of just -> 12 to 12.5 VDC