Battery dies. I have a Venox and I put a volt meter on the battery and with the headlight unplugged, it reads 14 volts. But, when I plug the headlight in the volt meter reads 13 volts and the battery will die after a while. Should i replace the Voltage Regulator or the Generator? How do i test these parts?

Not a lot of information there. How old is the battery? The first thing I'd do is have the battery "load tested". Just because a volt meter tells you that it has 12.3 volts doesn't mean it'll start your bike. The meter is designed not to put a load on the circuit being tested. Your bike starter puts a tremendous load on the battery. Most any automotive parts store will test the battery for free.

Here's how to check the charging system. To do this you need to fully charge the battery and you'll need a good Digital Volt Ohm Meter. Using the meter's function selector switch, set it to DC VOLTS with a range of 20 volts or greater. Connect the red meter lead to the positive battery post and the black meter lead to the negative battery post. Start the engine and bring it to a high idle. After about a minute or so, your meter should read between 14.5 and 15.0 volts. Any lower than 14 volts, your battery will not be charged.

If you don't have the minimum voltage at the battery in the previous test, you need to check the alternator to see if it's generating sufficient voltage. You'll have to follow the wires from your voltage regulator going to the lower left front of your engine until you come to a plug. Unplug the plug and look into the engine side of it. You'll see two metal contacts in the rubber plug. This is where you are going to test the voltage from your alternator. Since you'll be testing AC voltage, it makes no difference which meter lead goes into which contact, just one lead into each contact. Set your meter's function selector switch to AC VOLTS with a 50 volt or greater range. Start the engine and bring it to a high idle. Insert one meter lead into each of the metal contacts. Do not let the leads touch each other or the engine case or ground. Your meter should read at least 25 volts.

If you do not have the 25 volts from the alternator, your stator is bad and must be replaced. If you have 25 volts or more but not the 14 volt minimum at the battery, your voltage regulator is probably bad. Make sure you voltage regulator is properly grounded. Check the condition of the wire coming from the regulator going to the battery. This wire is usually larger in diameter than the other two going to the alternator.

Good Luck
Steve

You charging system should be putting between 14.5 to 15.0 volts to your battery. Those dash gauges are not the most accurate in the world. The first thing I'd do is have the battery "load tested". An automotive parts store will usually do this for you at no charge. Take the battery out and take it to them.

You need to check the charging system. To do this you need to fully charge the battery and you'll need a good Digital Volt Ohm Meter. Using the meter's function selector switch, set it to DC VOLTS with a range of 20 volts or greater. Connect the red meter lead to the positive battery post and the black meter lead to the negative battery post. Start the engine and bring it to a high idle. After about a minute or so, your meter should read between 14.5 and 15.0 volts. Any lower than 14 volts, your battery will not be charged.

If you don't have the minimum voltage at the battery in the previous test, you need to check the alternator to see if it's generating sufficient voltage. You'll have to follow the wires from your voltage regulator going to the lower left front of your engine until you come to a plug. Unplug the plug and look into the engine side of it. You'll see two metal contacts in the rubber plug. This is where you are going to test the voltage from your alternator. Since you'll be testing AC voltage, it makes no difference which meter lead goes into which contact, just one lead into each contact. Set your meter's function selector switch to AC VOLTS with a 50 volt or greater range. Start the engine and bring it to a high idle. Insert one meter lead into each of the metal contacts. Do not let the leads touch each other or the engine case or ground. Your meter should read at least 30 volts.

If you do not have the 30 volts from the alternator, your stator is bad and must be replaced. If you have 30 volts or more but not the 14 volt minimum at the battery, your voltage regulator is probably bad. Make sure you voltage regulator is properly grounded. Check the condition of the wire coming from the regulator going to the battery. This wire is usually larger in diameter than the other two going to the alternator.

Good Luck
Steve

You guessed exactly what I was going to say. Even a new battery is not fully charged when you install it in your bike. Between your riding and then leaving your key on, the battery died. It was going to happen sooner or later whether you left your key on or not. This way at least you were not stuck on the side of the highway. Man, I hate that.


You need to check the charging system. To do this you need to fully charge the battery and you'll need a good Digital Volt Ohm Meter. Using the meter's function selector switch, set it to DC VOLTS with a range of 20 volts or greater. Connect the red meter lead to the positive battery post and the black meter lead to the negative battery post. Start the engine and bring it to a high idle. After about a minute or so, your meter should read between 14.5 and 15.0 volts. Any lower than 14 volts, your battery will not be charged.

If you don't have the minimum voltage at the battery in the previous test, you need to check the alternator to see if it's generating sufficient voltage. You'll have to follow the wires from your voltage regulator going to the lower left front of your engine until you come to a plug. Unplug the plug and look into the engine side of it. You'll see two metal contacts in the rubber plug. This is where you are going to test the voltage from your alternator. Since you'll be testing AC voltage, it makes no difference which meter lead goes into which contact, just one lead into each contact. Set your meter's function selector switch to AC VOLTS with a 50 volt or greater range. Start the engine and bring it to a high idle. Insert one meter lead into each of the metal contacts. Do not let the leads touch each other or the engine case or ground. Your meter should read at least 30 volts.

If you do not have the 30 volts from the alternator, your stator is bad and must be replaced. If you have 30 volts or more but not the 14 volt minimum at the battery, your voltage regulator is probably bad. Make sure you voltage regulator is properly grounded. Check the condition of the wire coming from the regulator going to the battery. This wire is usually larger in diameter than the other two going to the alternator.

You didn't say what year or model bike you're working on but either way, I'd check the charging system. I'd also take the battery back where I bought it and have it checked. I've seen brand new batteries go bad. Have it checked just to make sure it is good. You need to have it "load tested", not just put a voltmeter on it. A voltmeter doesn't tell you the condition of the battery because the meter is designed not to put a load on the device you're checking. The starter puts a tremendous load on the battery and if it's got a shorted cell, the voltage will drop below 11 volts when trying to start the bike.

You need to check the charging system. To do this you need to fully charge the battery and you'll need a good Digital Volt Ohm Meter. Using the meter's function selector switch, set it to DC VOLTS with a range of 20 volts or greater. Connect the red meter lead to the positive battery post and the black meter lead to the negative battery post. Start the engine and bring it to a high idle. After about a minute or so, your meter should read between 14.5 and 15.0 volts. Any lower than 14 volts, your battery will not be charged.

If you don't have the minimum voltage at the battery in the previous test, you need to check the alternator to see if it's generating sufficient voltage. You'll have to follow the wires from your voltage regulator going to the lower left front of your engine until you come to a plug. Unplug the plug and look into the engine side of it. You'll see two metal contacts in the rubbber plug. This is where you are going to test the voltage from your alternator. Since you'll be testing AC voltage, it makes no difference which meter lead goes into which contact, just one lead into each contact. Set your meter's function selector switch to AC VOLTS with a 50 volt or greater range. Start the engine and bring it to a high idle. Insert one meter lead into each of the metal contacts. Do not let the leads touch each other or the engine case or ground. Your meter should read at least 25 volts is the bike is a Sportster, 30 if it's a Big Twin.

If you do not have the 25 volts from the alternator, your stator is bad and must be replaced. If you have 25 volts or more but not the 14 volt minimum at the battery, your voltage regulator is probably bad. Make sure you voltage regulator is properly grounded. Check the condition of the wire coming from the regulator going to the battery. This wire is usually larger in diameter than the other two going to the alternator.

Good luck
Steve

You need to check the charging system. To do this you need to fully charge the battery and you'll need a good Digital Volt Ohm Meter. Using the meter's function selector switch, set it to DC VOLTS with a range of 20 volts or greater. Connect the red meter lead to the positive battery post and the black meter lead to the negative battery post. Start the engine and bring it to a high idle. After about a minute or so, your meter should read between 14.5 and 15.0 volts. Any lower than 14 volts, your battery will not be charged.

If you don't have the minimum voltage at the battery in the previous test, you need to check the alternator to see if it's generating sufficient voltage. You'll have to follow the wires from your voltage regulator going to the lower left front of your engine until you come to a plug. Unplug the plug and look into the engine side of it. You'll see two metal contacts in the rubber plug. This is where you are going to test the voltage from your alternator. Since you'll be testing AC voltage, it makes no difference which meter lead goes into which contact, just one lead into each contact. Set your meter's function selector switch to AC VOLTS with a 50 volt or greater range. Start the engine and bring it to a high idle. Insert one meter lead into each of the metal contacts. Do not let the leads touch each other or the engine case or ground. Your meter should read at least 30 volts.

If you do not have the 30 volts from the alternator, your stator is bad and must be replaced. If you have 30 volts or more but not the 14 volt minimum at the battery, your voltage regulator is probably bad. Make sure you voltage regulator is properly grounded. Check the condition of the wire coming from the regulator going to the battery. This wire is usually larger in diameter than the other two going to the alternator.

Good Luck
Steve

To check the charging system, you need a DVOM (Digital Volt Ohm Meter). Make sure the battery is fully charged or you'll get a bad reading. With the battery fully charged, connect the meter "across" the battery but connecting the meter's red lead to the positive battery post and the black lead to the battery negative post. Put the meter's function selection switch in DC VOLTS, 50 VOLT RANGE. Start the engine and bring it to a high idle. Your meter should read 14.5 to 15.0 volts.

If it does not, you need to check the alternator output. Find the plug in the lower front of the engine case where the regulator wires plug into the engine. Unplug the plug and look into the engine side of the plug. There are two metal contacts inside the plug. These metal plugs are where we are going to put our meter probes to test the output. Put on probe on each metal plug. It makes no difference which probe goes where just don't let them touch the engine case or each other. Put the meter's function selector switch in AC VOLTS, 50 VOLT RANGE . Start the engine and bring it to a high idle. Touch the meter probes to the two metal plugs in the engine case. Your meter should read 30 volts or greater.

If the alternator does not read thirty volts, make sure you meter is in the AC VOLT scale and you've got good contact on the metal plugs in the engine. If you still don't read at least 30 volts, you stator is bad and must be replaced. If you 30 volts or more but you don't have the 14 volts at the battery, the regulator is probably bad. Make sure the regulator is grounded properly.

Good luck
Steve

It's possible but let's do a little mechanicing first.

You need to put a FULLY charged battery in the bike. Then, connect a DVOM (digital volt ohm meter) across the battery by connecting the meter's red lead to the positive battery post. Then, connect the black meter lead to the negative battery post. Put the meter's function switch in 'DC VOLT, 20 VOLT OR GREATER scale. Make sure the meter is in DC volts. You should read about 12.3 volts. Start the engine and bring it to a high idle. The meter should slowly build up to between 14.5 to 15.0 volts. If not. proceed to the next step.

Look from the right side of the bike just behind the rear cylinder and just in front of the starter and you'll see a plug. If you can't find it this way, follow the two wires from your voltage regulator back to the plug. It'll be a round looking plug on most Sportsters. Unplug the plug. Look inside the plug half that comes from the engine and you'll see two metal connectors. This is where you're going to test the output of the alternator. First put the meter's function switch in AC VOLTS, 50 VOLT RANGE. Since we're measuring AC voltage on this test, it makes no difference which meter lead goes to which metal connector in the plug. Start the engine and stick a meter lead into each of the metal pieces inside the engine half of the plug. With the engine at high idle, you should read at least 25 volts.

Now, If you don't have the 25 volts at the engine, your alternator is bad. If you do have the 25 volts or more at the engine but not the 14.5-15.0 at the battery, your regulator is bad. I hope this helps,

Good Luck
Steve

With the battery fully charged, use a DVOM (digital volt ohm meter) to check the output of the charging system. Connect it across the battery, red meter lead to positive, black meter lead to negative. Put the meter's function switch in DC VOLTS, 20 VOLT range. Start the engine and bring it to a high idle of about 1500-2000 RPM. The meter should read 14.5 to 15.0 volts.

If the meter does not read correctly, unplug the regulator where it enters the front of the engine case. You'll be measuring the AC voltage at the engine case side of the plug. Put your meter's function switch in AC VOLTS, 50 VOLT range. Put one meter lead into one metal contact in the plug and the other lead into the other metal contact in the plug. Makes no difference which lead goes to which metal contact. Start the engine and bring it to a high idle. You should read 30 volts or better.

If you do not read 30 volts at the engine, your stator is bad. If you have 30 volts or more at the engine but low voltage at the battery, your regulator is probably bad. This is a simple test and it's accuracy is about 90% or so.

Good Luck
Steve

Marshall:

First, your battery MUST be fully charged to perform these test. You'll need a good DVOM (digital volt ohm meter) but an analog meter will work. Connect the meter across the battery with the read lead to the positive post and the black meter lead to the negative post. Put the meter's function switch in DC VOLTS, 20 VOLT range. Start the engine and bring it to a high idle. Your meter should show a slow build up of voltage over about a thirty second period of time. It should read 14.5-15.0 volts.

If not, you'll need to test the alternator. Unplug the regulator at the front of the engine. Look inside the connector in the engine case and you'll see two metal connectors. Put one meter lead into each contact. It makes no difference which lead goes to what connector because we're checking AC voltage. Now, set your meter function switch to AC VOLTS, 50 VOLT RANGE. Start the engine and bring it to high idle. You should read at least 30 volts.

If you read 30 volts or more at the alternator but less than 14 volts at the battery, replace the regulator. Naturally, less than 30 volts at the alternator, replace the stator.

Good Luck
Steve

First, your battery MUST be fully charged to perform these test. You'll need a good DVOM (digital volt ohm meter) but an analog meter will work. Connect the meter across the battery with the read lead to the positive post and the black meter lead to the negative post. Put the meter's function switch in DC VOLTS, 20 VOLT range. Start the engine and bring it to a high idle. Your meter should show a slow build up of voltage over about a thirty second period of time. It should read 14.5-15.0 volts.

If not, you'll need to test the alternator. Unplug the regulator at the front of the engine. Look inside the connector in the engine case and you'll see two metal connectors. Put one meter lead into each contact. It makes no difference which lead goes to what connector because we're checking AC voltage. Now, set your meter function switch to AC VOLTS, 50 VOLT RANGE. Start the engine and bring it to high idle. You should read at least 30 volts.

If you read 30 volts or more at the alternator but less than 14 volts at the battery, replace the regulator. Naturally, less than 30 volts at the alternator, replace the stator

Good Luck
Steve