Topic: Regulator / Battery / Starter - PLEASE CONFIRM

[EverettShadowbrook]

Ok. If everyone could please help me confirm my diagnosis. I have gone through all the archives and tested everything accordingly.

76 CB750

I have been having issues starting the bike from the electric start when cold. When hot starts up pretty well. Battery is 4 months old. Cranked the starter good when I bought it

Used the multi-meter to test voltage of the battery fully charged, with key switched to on, while idling, and while revving above 3K.

Testing the fully charged battery I get about 13 volts with the ignition switched off. Turn it on and the voltage drops to 12.3-6. When pushing the start button voltage drops to 8-9 volts. The starter solenoid will click; starter will turn once then keep clicking. Sounds like a bad battery right?

I kickstarted the bike then watched the voltage rise as I revved the engine. Voltage is supposed to stop at 14.5 volts, but mine keeps going up. All the way to 16 volts before I stopped in fear of driving my neighbors crazy. So my charging system is over charging the battery, right? How much voltage is too much? So from this I gather that my regulator is shot because it is not stopping the excess voltage from hitting the battery.

Next I switched batteries with a good working/cranking battery from a friend. It started with the electric start no problem. Although the starter seemed a bit lazy.

So if you have read this far, here is my diagnosis, please chime in if you think I’m wrong.

-   My charging system has been over charging my battery due to a faulty regulator. The regulator won’t switch off, allowing excess charge to reach the battery. 16 volts(is this too much?) – new regulator required.

-   My battery is done due to over charging. It has reduced cranking power and can’t handle the load of the starter (CCA are diminished).

-   My Starter may need refurbing or replacement due to its lazy nature. Or could it be the solenoid?

Thanks for reading this novel. If you reply and confirm my diagnosis I will send you a Christmas card! Thanks   

[Kframe]

Yep, sounds like the regulator has crapped out, and the excess voltage has toasted the battery.
The starter is probably still good, but DON'T use it until you've sorted out the fried battery.
If the voltage is too low, then the current being drawn by the starter goes way up to compensate and that high current will kill your starter pretty soon.

So, step one, steal underpants.  No wait, that's from South Park.   
For real, step one, get a new regulator, step two, new battery, step three, RIDE!

-K

[Spanner 1]

The other test you could have done was to see what the charging voltage maxed at with the good battery still in the bike. Still got it ?...if topped-out under 15v then obviously first battery is bad.....or regulator points could be stuck ( they are cleanable ).

[SiliconDoc]

 Adjust the regulator:

[cookindaddy]

Also check/clean the heavy cable lugs at the starter solenoid and the battery terminal. Make sure they are nice and shiny and tight.

[Alan F.]

Also check/clean the heavy cable lugs at the starter solenoid and the battery terminal. Make sure they are nice and shiny and tight.

While you're at it you could clean the battery's ground lead to the frame for good measure.

[BVCB650]

Volts should go no higher than 14.0 to 15.0.

[EverettShadowbrook]

Thanks everyone. While I has testing the charging system I did clean all connections and plugs an grounds, so I don't think corroded or loose connections are contributing to my issue. Looks like I will be regulator shopping at work today. Oregon Motorcycle parts seems to have a nice unit.   

[bistromath]

Yep, sounds like the regulator has crapped out, and the excess voltage has toasted the battery.
The starter is probably still good, but DON'T use it until you've sorted out the fried battery.
If the voltage is too low, then the current being drawn by the starter goes way up to compensate and that high current will kill your starter pretty soon.

So, step one, steal underpants.  No wait, that's from South Park.   
For real, step one, get a new regulator, step two, new battery, step three, RIDE!

-K

Don't worry about the starter, as the lower voltage will actually cause it to use LESS current, not more. You won't fry it. But the regulator is definitely toast, or at least maladjusted. The Oregon Motorcycle unit is supposed to be pretty good. Check ALL electrical connections, and if you still have a lazy starter it might need to be rebuilt.

[Trav-i]

I highly recomend Oregon Motorcycle parts.  I got one of his solidstate regulator/rectifiers, and am extremely happy with it.  I know he puts quality in all his parts so I recomend picking one up from him.

[EverettShadowbrook]

Just ordered a regulator and rectifier from oregon motorcycle parts. Hopefully this helps my situation out. I will report back after install of these pieces and a new battery.

[Kframe]

Yep, sounds like the regulator has crapped out, and the excess voltage has toasted the battery.
The starter is probably still good, but DON'T use it until you've sorted out the fried battery.
If the voltage is too low, then the current being drawn by the starter goes way up to compensate and that high current will kill your starter pretty soon.

So, step one, steal underpants.  No wait, that's from South Park.   
For real, step one, get a new regulator, step two, new battery, step three, RIDE!

-K

Don't worry about the starter, as the lower voltage will actually cause it to use LESS current, not more. You won't fry it. But the regulator is definitely toast, or at least maladjusted. The Oregon Motorcycle unit is supposed to be pretty good. Check ALL electrical connections, and if you still have a lazy starter it might need to be rebuilt.

That is incorrect.  A DC motor fed with lower voltage than designed will draw more current in an attempt to do the same amount of work.  Furthermore, if the armature is turning slower the current is "trapped" for a longer time increasing the heat in the wrappings. 

Low voltage WILL kill DC motors (like your starter).
-K