Topic: 750K not charging. Scratching my head...

[Bonz55]

Hey all,

I know this has been discussed 100 times before. I have searched all the related posts I can find and tried everything others have suggested. All my components test okay and I'm at a bit of a loss of which direction I should go next. In case someone would like to investigate along with me...here are the symptoms....

- Battery would slowly not hold a charge. Bike ran fine on a charged battery.
- One day, bike randomly turned off (instead of dying slowly) while riding a short distance. Battery was hissing. I then changed out the regulator / rectifier with a new one.
- After installing the new regulator / rectifier...bike was charging the battery per normal. I rode it once and it died while coming out of first gear. No response from the battery after this. 7A fuse blew.
- I have also had it die while blowing the horn before two different times. It has now died twice from coming out of first gear.

- I have checked....
: Good battery
: Coils check good
: Stator checks good
: regulator / rectifier diodes check good
: Wiring hardness and all connections look solid. I can't seem to find an obvious short anywhere in the system.
: A tiny bit of rust on the top of the electric starter solenoid but it works fine.

Thew new regulator / rectifier WAS working just fine and now it seems like the bike isn't charging the battery at all. It holds about 12.3v no matter the RPM.

Any ideas what I can do next? Thanks for any advice.

[flybox1]

How did you clean your block connectors?
Does it have the original ignition switch and controls? 
Any hard bends in the loom, or cracked sheath between the headlamp and bars?
Removed the alt cover to verify connections hiding there are good?
What is the condition of your fuse block...front and back?  Any hot spots?
Grounds clean with solid contact?

Run thru this and report back.
http://www.hondachopper.com/garage/troubleshooting_charging_system/troubleshooting_charging_system.pdf

[Bonz55]

Thanks for the quick reply.

I haven't cleaned the block connectors but wasn't aware they needed it. Do I look for something obvious there? Nothing caught my eye enough to think about it honestly.

It doesn't have an OEM ignition and it is a bit of a hard turn on the wires from the key to underneath the fuel tank but I checked it pretty good yesterday and didn't see anything worn or frayed. So hard bends...yes but cracks in the sheath...not that I have found.

Fuse box looks good front and back. No hot spots at all.

Grounds are clean with solid contact. Only rust I can find is on the starter solenoid but it isn't much and the starter works well.

I actually spent a couple hours and ran through that guy's instructions you posted yesterday and everything checks out just fine.

[flybox1]

I actually spent a couple hours and ran through that guy's instructions you posted yesterday and everything checks out just fine.

hmmm...sounds fishy to me.
what were your battery readings at the various RPM?
whats your voltage drop thru the ignition switch?

read   http://forums.sohc4.net/index.php?topic=136310.0

[Bonz55]

Ignition off - 12.8
Ignition on - 12.7...falls slowly
Bike running (no matter the RPM) - 12.3 - 12.4

So 4,000 RPM.... 12.4v

Brand new regulator / rectifier that was working fine before (or at least it appeared to be).

[flybox1]

Ignition off - 12.8
Ignition on - 12.7...falls slowly Fine
Bike running (no matter the RPM) - 12.3 - 12.4  Too low once you're over 3000RPM

So 4,000 RPM.... 12.4v   Should be 14.5v at the battery at 4k rpm

Brand new regulator / rectifier that was working fine before (or at least it appeared to be).

I actually spent a couple hours and ran through that guy's instructions you posted yesterday and everything checks out just fine.

Dont ignore your test results.  More investigation on your part is needed.

[Bonz55]

Yup, that part I'm aware of. I'm just curious what others would do next I guess is my question. Seems like all the components test fine but the system isn't charging the battery.

[TwoTired]

The main fuse should be at least 15 A not 7A.  That ought to fix fuse blowing issue.

No offense, but we need to see measurement numbers.

First step in troubleshooting is verifying the basics.  It clearly doesn't work cause you've overlooked something.  So, we can't succeed if we just accept your report of "it's good".

Charge battery disconnect from bike. Let rest 2 hr.  Report voltage at terminals.
Connect battery to bike. Kick start. Give us a battery voltage map ; battery voltage at 1000, 2000, 3000, 4000, 5000 rpm.
Repeat map recording with lighting off.
This will verify a problem exists and the nature of it.

Place one meter probe on the POS terminal and the other meter probe on the black wire for the vreg.  Turn on all lighting and run the bike. Report meter voltage.
Repeat above with one probe on the NEG battery terminal and the other on the vreg green connection.  Report meter voltage.

This will tell us which way to proceed for cause investigation.

Cheers,

[Bonz55]

No offense taken haha I'm learning as I go.

The main fuse IS 15A. That isn't the one that blew. It was the 7A that blew.

If you're looking for only the readings you have asked for... I think I gave them above unless I missed something.

Battery after charge - 12.8
Battery with ignition on - 12.5 - 12.7
Battery at ALL rpms - 12.3v

In regards to your vreg test.... I have a black and white (instead of green) wire

Seem right? Want me to do the test on the white wire?

[MetroRedneck]

If you got that regulator off of amazon or ebay, try swapping the white and black wires.  They are wired backward often.

[Bonz55]

Tried swapping and no result. Reads 12.4v with bike on at all RPM

[flybox1]

Vreg/rect combo unit?

[Bonz55]

Yes sir it's a combo

Was working fine when I first got it so I'm not sure if it's the unit or something else.

[calj737]

- Battery would slowly not hold a charge. Bike ran fine on a charged battery.
- One day, bike randomly turned off (instead of dying slowly) while riding a short distance. Battery was hissing. I then changed out the regulator / rectifier with a new one.

- I have checked....
: Good battery
It holds about 12.3v no matter the RPM.

I question that your battery is any good any longer. "Hissing" would make me very suspect that the battery wasn't so cooked as to lose all electrolyte. Jumping to the conclusion that the R/R is the culprit is presumptuous.

You need to fully charge the battery, let stand several, then measure its voltage. Then do so again after a few more hours. If it never reaches its full capacity with no load, and also loses charge while resting, this is a clear indication of a bad battery. Every other electrical test is superfluous until your battery is verified. Or replaced with a known good and the bike ridden for component testing.

My $0.035 worth-

[Bonz55]

Oops! Forgot to mention that I'm using a brand new battery. The hissing battery is no more. I only included that piece of information in case it was helpful diagnosing another issue.

Sorry I wasn't clear about that.

[calj737]

Oops! Forgot to mention that I'm using a brand new battery. The hissing battery is no more. I only included that piece of information in case it was helpful diagnosing another issue.

Sorry I wasn't clear about that.

Ah, thanks for that.

[Dunk]

What voltage do you get at black terminal of voltage regulator key on and key on idling? What voltage at the white terminal?

You could try jumping the field coil full battery voltage briefly and see if it charges, that would eliminate the regulator as a problem.

[TwoTired]

I was trying to get info on what the vreg sense terminals were getting compared to a tual battery voltage.

I will warn you that jumpers bypassing an electronic regulator can damage the regulator, as can reversing connection polarities.

Taking the vreg portion out of circuit and applying voltage directly to the field coil should make the alternator produce max output for any given rpm.

Cheers,

[Bonz55]

Dumb question but... red end of volt meter on positive terminal of battery and black end on the black lead from vreg?

Only asking because my knowledge of this stuff is not tip top and want to make sure I'm giving you an accurate reading.

Key on at idle: black... 12.4v.  White.... .5v

Key on bike off: black.... 11.9v.  White.... 367. Lol

White lead bad ya think?

[calj737]

Correct me if I'm wrong, but withkey OFF, BLACK should be 0v. It's switched from RED with the key..

I'd like to see you re-run that test, but between key positions, touch the meter probe ends together to reset your meter.

...And what voltage scale is your meter set to?

[magnum56]

Dumb question but... red end of volt meter on positive terminal of battery and black end on the black lead from vreg?

Only asking because my knowledge of this stuff is not tip top and want to make sure I'm giving you an accurate reading.

Key on at idle: black... 12.4v.  White.... .5v

Key on bike off: black.... 11.9v.  White.... 367. Lol

White lead bad ya think?

NO ...  All voltage readings should be made with the black (com) probe connected to a ground, and the red probe used to measure the voltage at any single point in the chain.

For instance, with the black probe connected to the (-) negative side of the battery, measure the voltage at the battery (+) positive terminal with your red probe.  Then move the red probe to the black (sense) wire on the regulator.  They want to know if the voltage at the regulator wire is indicating full battery voltage, or if there is substantial voltage loss somewhere.   

[scottly]

Key on at idle: black... 12.4v.  White.... .5v

12.4v on the black is good, but only .5v on the white indicates your regulator is at fault.

[TwoTired]

Dumb question but... red end of volt meter on positive terminal of battery and black end on the black lead from vreg?

Yes, this will report directly any voltage lost between those two points
Same is true for the ground path between NEG and regulator.

Key on at idle: black... 12.4v.  White.... .5v

Not good.  At idle the white should get full batt voltage for max alternator output.

Key on bike off: black.... 11.9v.  White.... 367. Lol

White lead bad ya think?

White reg output bad, I expect.  The reg may have been cooked.
See if it charges when the reg output is disconnected and the black jumped to the white field coil input directly.  Watch out for overcharge when the rpms are upped.

Cheers,

[Bonz55]

Tested negative battery lead to white and black wire this time with key on...

Black - 24v
White - 11.8v

[b52bombardier1]

Was your 24 volt number AC or DC volts?

Rick

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