I am working on a Force 50 yr around 1986. It does not charge the battery. I checked stator for shorts and opens also the rectifier bridge is ok. I am an engineer. Can or do the magnets loose magnetism and not produce enough induced current into the coils. The stator coil puts out 8 volts RMS. Thanks Mike

Its better u take it to a motorcycle service, they can check the voltage that the scooter produces to charge the battery, maybe its the regulator or the magnetic field.

could be the stator or rectifier. rectifiers are easy to test since they're just a diode bridge to convert ac to dc. you'll need a service manual to check the stator. check the bluetraxx forum for one maybe.

Check the fuses first, (make sure they are in place and properly seated, No dirty contacts, take each one out). Check the stator next. There are three wires coming out of the rear of the left cover. They are all the same color and size. Unplug this plug and test the stator with an ohmmeter. resistance between any two wires in any direction should be very low (0.2 to 1 ohm). There should be no open leads or shorted (zero ohms) leads. If that is OK, change the regulator/rectifier (It's cheaper and easier).

Check for AC from the stator to the charge rectifier, then check for DC on the rectifier. if you have AC but no DC replace the rectifier, if you ahve no AC the stator is suspect. Assuming all fuses are checked and ok

Check the stator for AC output to the charge rectifier, if present stator ok, then check DC on DC side of rectifier if not present change the rectifier, ssuming all fuses have been tested

Locate the three wires (usually yellow) that come from the stator to the regulator/rectifier. They should be on a connector near the battery. Disconnect the wires and check the resistance of the stator leads between each other (3 checks) and from each lead to ground. There should be approximately equal resistance from lead to lead and no continuity to ground. Also check for AC voltage between each lead with the engine running. These readings should be approximately equal and should increase when throttle is applied to about 60-90ACV.
If the stator resistance and output check out, your regulator/rectifier is bad.
Unfortunately stator failure is common on these models and the engine must be removed for replacement.
Another common problem is that the connector itself will corrode/melt. Honda sells a replacement lead kit that you can install, or you can just hardwire the stator to the reg/rect.

run an ohm test on the stator wires, make sure you get readings through all combinations of any 2 wires. if you don't get an ohms reading between 2 wires that means you have a broken stator winding and the stator needs to be replaced. hook up a volt meter to your battery and test battery voltage at rest (bike off), at idle (bike on and idling should be at least 12.5 - 13 volts), and steady around 3 - 4000 rpms (should be around 13-14.5 volts. if it exceeds 15 volts your regulator is bad and needs to be replaced. if all numbers are about what I said, have your battery tested. If your battery is over 1.5 years old it should be replaced anyway.

FIRST OFF, EVEN THOUGH THE BATTERY IS NEW TO YOU, IT MAY HAVE BEEN ON THE SHELF AT THE DEALER FOR SOME TIIME. VERIFY A GOOD BATTERY WITH THE APPROPRIATE TESTER. AFTER THAT YOU CAN CHECK YOUR STATOR BY VERIFYING CONTINUITY AND OPENS IN THE STATOR HARNESS. EASIER WAY IS TO DISCONNECT THE BATTERY AFTER YOU START THE BIKE AND IF IT CONTINUES TO RUN THE STATOR IS LIKELY OK. AND YOU SHOULD LOOK AT THE REG/RECT AT THAT POINT. YOU'LL NEED CORRECT MEASUREMENTS FOR THE READOUTS ON THESE TESTS. QUICK CHECK THE STATOR BY TESTING ACROSS THE 3 YELLOW LEADS. YOU SHOULD GET CONT. WITH ANY COMBINATION OF THE THREE WIRES. NOW TEST EASH YELLOW LEAD TO GROUND. THERE SHOULD BE "NO" CONT. BETWEEN ANY YELLOW AND GROUND. IF THERE IS, IT IS SHORTED AND WILL NEED REPLACING.
ON A BIKE OF THIS AGE IT ISNT UNUSUAL FOR THE STARTER BUTTON TO "RESIST" SOMETIMES. THIS IS IN THE PSUH BUTTON ITSELF.SOMETIMES YOU CAN REPAIR THESE CONTACTS AND SOMETIMES YOU CANT. IF IT CLICKS WHEN YOU PRESS THE START BUTTON, THAT COULD BE THE START RELAY OR A BAD WIRE CONNECTION. CHECK THESE ALSO WHEN YOU CHECK YOUR BATTERY!

A bridge rectifier is in your circuit to make "rectified DC" from the "AC" your alternator produces. Of course you need DC to charge the battery.

Simple method - no ohm meter required.

Get a flashlight battery, a flash light light and two paper clips. Fasten one around the light and tape it to the + end of the battery with the tip of the light on the tip of the battery. You will have to manipulate #2 paper clip onto the bottom of the battery as you insert it here and there. Hold the thought.

A bridge rectifier is composed of two or four or maybe more diodes. A Diode allows power to travel in one direction but not the other. When this happens, the "top" part of the AC cycle passes through the diode but the "bottom" part does not. (remember what AC looks like on an oscelescope? - I cant remember how to spell it)

What does that mean to you? ... with the battery out of the circuit and the rectifier unplugged, start sticking the paper clip into first one then another slot. If you get light at all terminals, (or any pair) your diodes are shorted. Same story if you get NO light at all terminals (or any pair).

If your rectifier is good ... you should get light in one direction (some terminals) then turn the polarity around on the same terminals and you chould get no light.

If you have a ohm meter, you should read open in one direction and short in the other direction.

If this is getting too deep for you ... let me know I will try again.

If your rectifier is bad, remove it and take it with you to the Honda Shop parts place to make sure you get a exact replacement ... while there, ask the counterman if he or she can check it for you.

I hope this helps you out.

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Thanks

a

Sounds like regulator/rectifier, stator, or charging rotor.