Hey the lights are going dim. Hey my bike stalled. Hey my bike won’t start. Somewhere along the way most of us have experienced this type of scenario. You go out for a ride and sometime during that ride, hopefully while you are still close to home you seem to...

You are going to need a multi-meter that can measure volts and ohms and a few other tools to gain access to the battery. Remember when using a multi-meter you may have to set the ranges for the measurement, use the range closest to the desired reading. First check all of the wires and connections to make sure a connector didn’t come loose or a wire did not rub through on something and short out or get cut in two. If all looks good than start the bike. If the bike wont start jump it or try charging the battery to get it started. Once it is running check the voltage at the battery while it runs. You should have between 13.8 – 14.4 DC volts. As you bring the idle up and rev the engine the voltage should increase but it should never go over 14.7 volts. Anything over that and it is overcharging which is just as dangerous. Overcharging will destroy a battery. If it is any lower the charging system is not charging the battery. If it seems to be charging turn the bike off and put the headlights on and leave them on for a few minutes. You will probably see the battery voltage drop bellow 11 volts. A good battery should not drop bellow 11.5 – 12 volts with the headlights on. If the voltage drops replace the battery and you are on your way. If you are not charging get ready for another test.

Next lets remove the connector for the stator that is located down by the crank of the engine, usually in the primary drive. Put the multi-meter to the ohms measurement and put each probe into the connector to the stator. You should have below 5 ohms usually 1-3 ohms. Next take one probe and insert it into one of the connector terminals and put the other one to the engine block or some source of chassis ground. It should read open or infinity. Next swap to the other terminal and you should see the same. The stator should not be shorted to ground. If the resistance is not correct or it is shorted to ground the stator needs to be replaced. Now for the final test on the stator. Set the multi-meter on A/C voltage, insert the probes into each of the connector terminals to the stator and start the bike. When the bike is running at 1000 rpm you should see about 30 A/C volts and as you increase the rpm you should see the voltage increase approximately 20 volts per 1000 rpm. If all of these checks pass than the stator checks out good.

            The only item left is the regulator and is most likely your source of disappointment. The regulator would also be the source for the overcharge concern if you find the system overcharging. Just be sure to double-check all of the wiring and connectors one more time before replacing the regulator. There is nothing worse than replacing a part and finding out a connector came loose and was the cause all the time.

Now once you know the cause of the concern it is time to replace the faulty part. You can refer to shop manuals for the procedure or at least know what you are dealing with if you decide to have the work done at a shop.