Author Topic: No Charging CB350 70’  (Read 1038 times)

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Offline Ringostar1982

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No Charging CB350 70’
« on: June 20, 2018, 03:59:48 AM »
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!

Offline Ringostar1982

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Re: No Charging CB350 70’
« Reply #1 on: June 20, 2018, 11:13:54 AM »
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?

Offline kslrr

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Re: No Charging CB350 70’
« Reply #2 on: June 20, 2018, 12:11:34 PM »
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.
Now  1972 CB350FX (experimental v2.0)
        1981 CB650c Custom with '79 engine (wifes)
        1981 CB650 engine
        2004 HD XL883C Custom
        1977 Yamaha XS750D (in progress)
Then 1972 CL175
        1964 Yamaha YGS-1T
No ride is a Bad ride

Offline Ringostar1982

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Re: No Charging CB350 70’
« Reply #3 on: June 20, 2018, 01:40:17 PM »
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.

Offline kslrr

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Re: No Charging CB350 70’
« Reply #4 on: June 21, 2018, 08:11:09 AM »
Why are you converting the listed values of 12.5 and 14.8 to 17.6 and 20.9?
Now  1972 CB350FX (experimental v2.0)
        1981 CB650c Custom with '79 engine (wifes)
        1981 CB650 engine
        2004 HD XL883C Custom
        1977 Yamaha XS750D (in progress)
Then 1972 CL175
        1964 Yamaha YGS-1T
No ride is a Bad ride

Offline Ringostar1982

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Re: No Charging CB350 70’
« Reply #5 on: June 21, 2018, 11:01:15 AM »
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. 


Offline Ringostar1982

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Re: No Charging CB350 70’
« Reply #6 on: June 27, 2018, 12:58:12 AM »
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