Topic: 72 CB350F not charging with lights on

[bking]

I am new to the form and I have spent some time searching for this problem. We are just finishing up a cafe build on this bike. I took it for about a 5 mile spin on Sat and when I got back the battery was dead. I ck the voltage output with the lights off and it was 12.2 at 1000rpms, 12.5 at 2000, 13.3 at 3000, 14volts at 4000 and above. It claims slow but it is charging.  With the headlamp and tail lamp on it is 12.3 volts at 4000 rpms.
We powder-coated the frame and painted everything else. So tomorrow I will ck all the grounds. If it does not charge then I will start checking all the different parts of the charging system. Just wondered if any body has any ideas.

Thanks Bruce

[CycleRanger]

How old is the battery?  How many watts is the headlight?

[camelman]

I had the same issue on a powder coated frame for a 350 twin. Make sure all major components can easily ground and clean all connections including fuses and fusible links. Dielectric grease helps too.

Doing everything I mentioned took care of my charging issues.

Camelman

[bking]

New battery, oem headlamp, a/m taillamp

[DavePhipps]

What voltage are you getting across the battery terminals while the bike is running?
Here's a link to a very in depth fault finding guide. The PDF is at the bottom of the page when you folow the link.
http://www.electrosport.com/technical-resources/diagnosis-center/fault-finding-guide 

[bking]

I have a test light that displays the voltage of the system (Power Probe III). The test light connects at the battery terminals. The voltage that I listed are off of the test light. I also have a dvom that I will do some more cks with over the weekend.

[DavePhipps]

Somehow I missed the numbers in your first post. That's what I get for replying before having my morning coffee. Obviously you are getting some charge, so I would go with checking grounds. I'll be doing this with my bike over the weekend,so I can feel your pain. I'm getting 12.01 at 3-4k RPM.

[bking]

Well guys I didn't get a chance to work on the charging system tonight. I had a problem the the turn signals that I worked on and got going. One more problem behind us and on to the charging system tomorrow and Sat. I will let you know what I find.

[CycleRanger]

You might want to use an ohmmeter to check the rectifier. It may have a bad diode.

[bking]

Thanks Cycle Ranger, I will check out everything shortly and let you know what I found.

[Bodi]

You just modified this bike, if I read your post correctly. You may be having a grounding problem, or some wiring harness issues. Particularly, on the 350/400, the alternator wires have bullet connections under the left engine cover: these are a common problem area.
The key question is: what modified electrical stuff did you add? The 350 has a low output alternator that is fine with the stock electrical components if the harness connectors and grounding are OK. Add a high wattage headlamp, electronic ignition, etc etc... and the alternator can not produce enough electrical power to get the voltage up to "full charge" level.
You have about 120 watts of power available from the alternator (I did not look up the actual number, but that's close).
The wattage drawn by a load changes with voltage, but it is exponential. Double the voltage and you draw four times the power. It doesn't sound like a big difference between 12.5V and 14.5V, but it's 35% more wattage load from the electrical devices.
The regulator limits the system voltage at about 14.5V but with too much load it never gets that high: the system voltage balances at whatever voltage the alternator, at 100% output, can push into the load. You can not add much load at all to a 350 before getting exactly the symptoms you describe.

[bking]

I didn't change much to the electrical side of things. It has  the stock headlight, no running lights, mini turn signals, and a aftermarket tail light that I believe has a standard 1157  bulb. With just the headlamp and taillamp on @ 4000 rpms she will only make 12.3 volts. Not sure on the amp output. I will bring home a amp gauge with me tonight. I am hopping it is just wiring connections and ground problems.
Thanks

[bking]

Ok every one I have a few questions. I am using some test in the FAQ section.

This is some of the test that I am doing.

Resistance testing of regulator wires. 
1.   While the bike is not running disconnect (-) battery lead and Black regulator wire.  Check for 0 resistance between (-) battery wire and Black regulator wire.
2.   Disconnect all regulator leads. 
a.   Test for resistance between I and F poles.  0 resistance is good.  If greater than 0 clean the regulator points. 
b.   Test for resistance between the white wire and ground.  Resistance between 4 and 8 ohms means the field coil is good.
   
V.   Testing the stator yellow leads. 
A.   Test wires 1 and 2, 1 and 3, 3 and 2 for ohm readings.  Less than 1 ohm means the circuit is good.  Greater than 1 ohm means poor connection.  Infinite resistance means that the coil has an open circuit or possibly a bad lead. 
B.   NOTE.  For GL1000 you need to disconnect/remove the permanent magnet rotor before continuing.  Set tester to insulation resistance and calibrate it to 0 to perform a wire insulation test on the stator.  Ground the negative test lead and touch the other lead to each of the three stator wires.  If the resistance is infinite then the coil is ok.  If not then the coil is shorted to ground. 
C.   Test the three stator wires in the harness of the motorcycle.  First disconnect the rectifier.  Set the tester to resistance.  0 resistance means all three wires are fine.  Greater than 0 means the wire is bad. 
D.   Check the wires for bad insulation.  Connect the black tester lead to ground.  Each wire should have infinite resistance.  Greater than infinite resistance means the wire has bad insulation. 

VI.   Check the five leads on the rectifier. 
A.   To perform a forward bias test first connect the red tester lead to the green ground lead. 
B.   With the black tester lead test all three yellow wires. 
C.   Resistance must fall between 5 and 40 ohms. 
D.   To perform a reverse bias test connect the black tester lead to the green ground lead. 
E.   With the red tester lead test all three yellow wire. 
F.   Resistance must be greater than 2000 ohms. 
G.   Connect the black tester wire to the red and white rectifier lead. 
H.   With the red test lead test all three yellow wires. 
I.   All three must have between 5 and 40 ohms. 
J.   Connect the red test wire to the red and white rectifier lead. 
K.   Test all three yellow wires with the black tester lead. 
L.   Resistance must be greater than 2000 ohms. 

VII.   Testing the harness plugs and leads. 
A.   Test each of the plug wires in the circuit for o resistance. 
B.   While the battery and rectifier are disconnected test the red and white harness rectifier wire to the (+) battery lead for 0 resistance. 


My results:

Test 1. I get 1.7ohms. It is suppose to be 0, so where do I check if it is not 0.
        2A.I am good at .1 should be 0
        2B Should be 4-8 and I am 4.8ohms.

Test A Checking the yellow stator leads. It does not say to unplug the rectifier. I did unplug it to do the test. Testing between all three yellow leads I get .8, Test is good if under 1.0.
 I don't remember any other stripe colors on the three yellow leads when I plug the harness to the stater under the starter cover. Is there any particular way they are suppose to be connected?
 
Test C does not make sense to me. Check all three stator wire. (what color? the yellow wires?)

Now on to test the leads at the rectifier unpluged. My manual said on the 350f to test between the red/white and all the yellow wires.
So with the red lead on the red white and the black on the yellow leads I get .8-.45-.45. Switch the red and black leads and I get 2.6-1.2-1.2. I don't even know if this is ok, but it is not even. My manual just said it should be high with the leads one way and low with them the other way.

I hope you guys can make something out of this mess and give me some more direction. 

I cleaned the battery leads and the ground wire under the tool box but they all looked pretty clean. I fully charged the new battery and started the bike. With no load at 4-5000 rpms the bike reached 15volts. At the same rpms with the headlight on low beam it quickly reached 12.6 volts. I took the bike out for about a 15-20 min ride with the headlight on. I was driving mostly city but not all. When I got back the battery not drained. It would start the bike just fine but I am sure it was down a little. So it may be charging some but not like it should.
Thanks again

P.S. One more thing I wanted to mention. I am getting some back feed in to oil pressure light. Key on engine off the oil light it bright. Start engine and the light is very dim. I ck the oil pressure and it is good. One more sign that something is not right in the wiring.