Erg0n wrote:isn t the only time the battery gets used is when you are turning on the motorbike? Eveything else runs off the alternator, Unless you leave your highbeams on while the car isn't running
Everything gets run by the alternator across the battery. If the alternator isn't working correctly then it'll run until the battery dies. And then you're borked.
ledzep12184 wrote:Yes, I do have a multimeter and a little help would be great. That electrical system on that bike is screwy.
Mmmkay,
Start with the simple stuff, charge the battery using a trickle charger and allow it to sit half an hour afterwards. Check the voltage DC using the mulitmeter, it should read at least 12.8 volts. If not you'll need to replace the battery.
Install the battery in the bike, making sure that all of the connections are tight. A loose connection means your bike won't start.
Start the bike and check the voltage DC across the battery, depending on your bike and the year it might be slightly more or slightly less then 12.8 volts.
Have someone rev the bike up to aprox 4000-5000 rpm while you check the voltage. It should be reading in the range of 14.0 to 15.0 volts depending on the type and age of bike. If it is then your charging system is fine. If not we've got to figure out what part is bad.
Trace those three yellow wires coming out of the alternator (left side engine case when you're sitting on the bike). Find where they're plugged in and disconnect them. You're now running on battery power.
Set the multimeter to volts AC.
What you'll have in the plug that you disconnected is three different spots where the wires come out. Call them A, B and C. You need to check the volts AC across each combination - AB, BC, CA at aprox 4000-5000 rpm (you'll need an assistant). You should be getting in the range of 60-80 volts AC off each combination.
If one is substantially lower, or doesn't work at all then you've got a bad coil in the alternator. If they all read way low you may need to replace the stator or the magnets.
Shut the bike off and set your multimeter to resistance (ohms). Stick the positive tester into one of the spots (ABC) and touch the negative to the frame or engine block. It should read infinite resistance. Repeat for the other three tests. If you find there is continuity - a resistance other then infinite, then you need to replace the stator (coils of wire).
If all of that checks out, then you need to check the wiring too the rectifier (which converts AC to DC). Just check for shorts or continuity problems using the methods described above.
There are specific methods for testing the rectifier... but those are. Well you need the manual, and you need to know exactly what bike you're doing it for. I couldn't tell you how to test yours correctly. Besides, most rectifiers come with a built in regulator, which makes it even tougher to test.
The regulator dumps excess current to ground - because you didn't say your battery had boiled over and exploded I will tell you right now the regulator... if it is a separate unit from the rectifier is fine.
Yikes! That's WAY too much typing, but you get the idea.
Having said all of that... the problem is rarely the alternator/charging system. It's usually a short to ground, or pinched wire, or a loose connection somewhere. People tend to say, "it's the alternator" because that's the easy way out. Then again without checking, what do I know?