Testing voltage regulator

May just need new brushes on alternator..need scrudrivr to check. Voltage regulator cud bbad. Batts not chargn...

A bad regulator or stator.

This is what I would suggest before just changing the stator out. Hope this helps.Okay first step is to check voltage on battery.Most times it is a low voltage battery and easiest to fix. Checking the charging system to see if the voltage regulator or stator is bad read this...

Step 1. Normally, you'd first load test the battery,
Start the engine and measure DC Volts across the battery terminals, the regulator should be putting out 14.3 - 14.7 vdc at 3600 rpm and 75 degrees F.


Step 2. To check the regulator unplug it from the stator. Take a test light and clip it to the negative terminal of the battery and then touch first one pin and then the other on the plug that goes to the regulator. If you get even the slightest amount of light from the test light the regulator is toast.

To do this with a meter which is more accurate: black lead to battery ground, red lead to each pin on the plug, start with the voltage scale higher than 12vdc and move voltage scale down in steps for each pin. Any voltage is a bad regulator.
You may get battery voltage on all three pins on the newer 3 phase regulators.
The no voltage is for older type regulators with diode indicating the diode is bad and the regulator needs replacing.


Step 3. On the other part of the disconnected regulator plug. Set the multimeter for Ohms x1 scale and measure for resistance across the pins of the stator. You should read something around 0.1 to 0.2 ohms for the TC88 32 amp system.


Step 4. Then check for continuity between each pin on the plug and frame/engine ground. The meter needle should not move (infinite resistance)(digitals will show infinite resistance) if the meter needle does move (indicating continuity)(digitals will show some resistance), recheck very carefully. If the meter still shows continuity to ground the stator is shorted (bad).


Step 5. Set the meter to read A/C volts higher than 30 volts (the scale setting for voltage should always be higher than the highest voltage you expect or you may fry the meter). Start the bike, and measure from one pin to the other on the plug (DO NOT cross the multimeter probes! - touch them to each other). You should read roughly 16-20 vac per 1,000 rpm.


Step 6. If the battery was good under load test, if the stator is NOT shorted to ground, and the stator is putting out A/C voltage, then the regulator is bad (most likely even if if passed step 2).


Generally the following is true:
Check your owners/service manual for the system amp output for your bike.
22 amp system produces about 19-26 vac per 1,000 rpm, stator resistance is about 0.2 to 0.4 ohms.
32 amp system produces about 16-20 vac per 1,000 rpm, stator resistance is about 0.1 to 0.2 ohms.
45 amp system produces about 19-26 vac per 1,000 rpm, stator resistance is about 0.1 to 0.2 ohms.

Step 1. First things first, load test the battery. Most places like Auto Zone will do it for free. Even if it measures over 12.5 vdc it can still be bad under a load. Battery is typically rated at 19 amp hours and 270 Cold Cranking Amps (CCA).

Start the engine and measure DC Volts across the battery terminals, the regulator should be putting out 14.3 - 14.7 vdc at 3600 rpm and 75 degrees F.


Step 2. To check the regulator unplug it from the stator. Take a test light and clip it to the negative terminal of the battery and then touch first one pin and then the other on the plug that goes to the regulator. If you get even the slightest amount of light from the test light the regulator is toast.

To do this with a meter which is more accurate: black lead to battery ground, red lead to each pin on the plug, start with the voltage scale higher than 12vdc and move voltage scale down in steps for each pin. Any voltage is a bad regulator.


Step 3. On the other part of the disconnected regulator plug. Set the multimeter for Ohms x1 scale and measure for resistance across the pins of the stator. You should read something around 0.1 to 0.2 ohms for the TC88 32 amp system.


Step 4. Then check for continuity between each pin on the plug and frame/engine ground. The meter needle should not move (infinite resistance)(digitals will show infinite resistance) if the meter needle does move (indicating continuity)(digitals will show some resistance), recheck very carefully. If the meter still shows continuity to ground the stator is shorted (bad).


Step 5. Set the meter to read A/C volts higher than 30 volts (the scale setting for voltage should always be higher than the highest voltage you expect or you may fry the meter). Start the bike, and measure from one pin to the other on the plug (DO NOT cross the multimeter probes! - touch them to each other). You should read roughly 16-20 vac per 1,000 rpm.


Step 6. If the battery was good under load test, if the stator is NOT shorted to ground, and the stator is putting out A/C voltage, then the regulator is bad (most likely even if if passed step 2).

i have the same problem, The most likely problem is that your charging
system is not working or your battery has a faulty or shorted battery cell.

The battery should be load tested at an
auto shop or motorcyle dealer.
This will verify if it is still okay.
It must be fully charged to do a load test.

You can connect a multimeter to the battery
terminals and see if the bike is charging.
Speed the bike up to about 3000 rpm
and see if the battery voltage is about 14 volts
or slightly higher.

If the voltage is only the same as the battery
or under 13 volts then the bike is not charging
properly.

This could be a faulty alternator stator coil
or a faulty regulator/rectifier unit.

The alternator stator connector
is under the seat. It has a white
connector with 3 yellow wires.

Unplug the connector and check the
"AC" voltage between each set of yellow
wires with the bike running fast idle.

Between any two yellow wires you should have
30-60 volts "AC"
Also, none of the yellow wires
should have any connection to ground.
You can check that with the ohms setting
on the meter.

If the stator voltage is low or none
then the stator coil under the
left engine cover will need to
be replaced.

If the voltage is okay on the stator
but not on the battery then
the regulator/rectifier unit is likely
faulty. There is no test, just replace
it if the stator voltage is good and
the battery is good.

To check for a drain just remove your
negative battery cable and put a test
light between the battery and the cable.
If it lights up with the key off, that
is a drain. Pop fuses until it goes off
to find the troubled circuit.

You need to check the output of your alternator. You'll need a DVOM (digital volt ohm meter) to check the outputs.

First connect the meter across your battery. Red meter lead to the positive terminal, black meter lead to the negative or a good ground. Put the function selector of your meter in DC VOLTS, 20 VOLT RANGE. Start the engine and bring it to a high idle, 2000 RPM. Your meter should read 14.5 to 15.0 volts. Turn all lights on and make sure the voltage stays the same.

If your meter reads low in this test, you need to check the output of the stator. On the lower left front of the engine, you'll see a plug where the voltage regulator plugs into the engine case. Unplug this plug and look into the part that is in the engine case. You'll see two metal contacts. These are what you're going to put your meter leads to in this test. Since the voltage is now AC volts, it makes no difference which lead goes to which contact. Put your meter's function selector in AC VOLTS, 50 VOLT RANGE. Start the engine and bring it to a high idle. Insert the meter leads into the contacts. The meter should read at least 30 volts AC voltage here.

If the alternator stator test fails, you need a new stator. If it passes the test but the voltage to the battery is low, you need a new regulator.

If both pass the test, you need to evaluate the current draw of any extra lights or other equipment that you may have put on the bike. If your equipment is drawing more current than the alternator is capable of producing, a slow drawdown of the battery is the results.

Good Luck
Steve

With a fully charged battery in the bike, connect a Digital Volt Ohm Meter to the battery, red lead to positive, black lead to negative. Set the meter's range to DC Volts, 20 volts or greater range. Start the bike. The meter should show a rapid build up to between 14.5 and 14.8 volts. If not, check the output of the alternator.

Look down near the oil filter and find the connector on the engine case where your voltage regulator plugs in. Unplug the connector and inspect both ends of it for broken or damaged connectors or wiring inside the plugs. Look down into the connector in the case and you should see two metal connections. This is what we're going to test next.

Put your DVOM meter into AC volts, 50 volts or better range. Make certain your meter is in AC volts as the voltage we'll be testing here is alternating current voltage. Start the bike up and bring it to a fast idle. Put one lead of the meter on each pin in the engine side connector. Since it's AC voltage, it makes no difference which lead goes to which pin. You should be reading at least 30 volts. If so, your regulator is probably bad. If not, your stator is the culprit.

Good Luck
Steve

get a test light and a schematic. unplug stator plug.start bike ,make sure battery has full charge. test each pin on connector that is attatched to the 3 yellow wires.should light on each pin. if all good check for burn marks around connectors, front & back sides, and on wires. if no power on yellow wires, stator problem. if power, plug connector together, now test for voltage in wires on the voltage regulator side of the connector, to see if the voltage is making it through the connector.if there is power to volt. regulator,test w/ multi meter across battery leads to see if there is charging voltage to battery,approximately 13-15 volts. if only battery voltage(12.2 or less) while bike is running,voltage regulator is no good.if charging good, but bike wont start after prolonged sitting(say overnight) a system amp draw test is needed to see if something is staying powered up while bike is not running, drawing down battery.