Cb350 dying

[Ericinwisconsin]

When I fully charge my battery my 1969 cb350 runs fine for about 30 minutes before it dies. If I push it down a big hill it will charge up briefly and run for about 5 minutes. The battery is new and was tested as ok by autozone today. I recently replaced the headlight bucket and undid some wires and reconnected. I may have disconnected something up there. To my understanding these I should be able to put my multimeter on the battery. When fully charged it should read around 12v with the key off. With the bike running it should read about 14v. Anyways wondering if anyone could give me some troubleshooting help. Thanks!

 

[Sonreir]

With the bike idling, you won't get much more (or possibly any more) voltage than you will from the battery alone. Let it idle to warm it up and rev it to 5000 RPM or so. Then you should see the 14V.

That is your first first. Let us know how it goes.

 

[AlphaDogChoppers]

A reading of 12 V is a damned near dead battery. Fully charged, a battery should read 12.6V or higher. A reading of 12V is only a 25% charge. If an AGM type battery, fully charged will read 12.8V or higher.

 

[Bert Jan]

sounds you disconnected the power from engine to loom. Engine runs on battery for about 30 minutes and when battery is drowned, bike dies. Logic. Like others said, rev it to 5000 and check voltage at battery. Should increase when you rev. If it stays the same, you disconnected some wires from engine to bike or your gennie/rectifier/regulator is fried. Report findings and we'll help you further.
Good luck!

 

[Ericinwisconsin]

Will check connections tonight and test at battery

 

[Ericinwisconsin]

Finally got back to the 350. Checked my connections and still not charging at the battery. Battery tested at autozone as ok. Essentially my bike will run about 45 minutes before slowly dying.

 

[SONICJK]

Check your alternator.
Theres three wires coming from the alternator.
Put your multimeter on AC, and touch the + lead to any of the 3, and then the - to one of the remaining 2.
You should be reading 30+ V across 2 of the pairs and 7ish across the third.
If that checks out move on to the rectifier, test the DC output as it leaves the unit.
If thats good, then check the input and output voltage at the regulator.
If all that checks out get a new battery 8)

Hopefully you can do all that in under 45 minutes

 

[spectacularspecimen]

Check your alternator.
Theres three wires coming from the alternator.
Put your multimeter on AC, and touch the + lead to any of the 3, and then the - to one of the remaining 2.
You should be reading 30+ V across 2 of the pairs and 7ish across the third.
If that checks out move on to the rectifier, test the DC output as it leaves the unit.
If thats good, then check the input and output voltage at the regulator.
If all that checks out get a new battery 8)

Hopefully you can do all that in under 45 minutes

Hey SONICJK, your post is seriously the most easy to understand test of the stator / alternator I have read to date. So props on that and thanks. I was wondering, what setting on my multimeter do I test this with? I have a meter with settings identical to these. Do I test it on the Diode function? Meter Settings: http://airborn.com.au/circuits/meter.jpg

Thanks for your help and I really hope you reply.

 

[SONICJK]

Hey man no problem.
Set your multimeter on whatever setting will read 30 volts and 7 volts.
Mine has 120 and 750 so use 120. If you have a lower setting that's above 40 ish use that.

 

[spectacularspecimen]

Hey man no problem.
Set your multimeter on whatever setting will read 30 volts and 7 volts.
Mine has 120 and 750 so use 120. If you have a lower setting that's above 40 ish use that.

I actually PMd you but you do not have to respond to that. Can I ask you a question and see what you think it may be, in regards to my charging? If not totally cool, I am just wanting to get riding and teaching myself so its a tough battle currently.

The situation is that the bike starts up fine, with electric start or first kick, but will not idle. I read that these bikes ideal on the battery and when the bike is at a higher rpm then say 3000 it runs okay but if you let off at all it will die. I tested a fully charged battery with it off and got 12.6 and with it on I was getting like 12.4 even when revving the RPMS super hard. I realize at this point it is probably the stator, regulator, or rectifier but do any of these symptoms or things I told you point to any of them specifically?

here is a video if you want to watch it: https://www.youtube.com/watch?v=3bVMemLNWWk

I really appreciate your help. I'd honestly be screwed without people like you willing to help me. If you cant answer or dont want to answer any of this please dont and I completely understand.

Thanks again

 

[SONICJK]

Does it die at idle with the battery fully charged?
Has the bike idled fine before and this happened all of a sudden? The reason I ask is that at 12.4 volts running your bike should idle just fine. With a fully charged good working battery and no charging system at all you can run for an hour or so.
That leads me to believe you're more into a carburetor problem than electrical.

To clarify that 12.4 is when it's revving hard? Take it down as low as it will go in the rpm range and take a reading.

First thing I'd do is test the battery (take
It to auto zone and have it load tested for free) Second I'd test the stator output, then the regulator output. If all that checks out then look toward your carbs.