Question by Eden's Rain: How can you tell if your motorcycle ('06 GSX-R600) needs a new alternator (aka: "generator")?
I just bought a brand new battery three months ago and had the dealership install it. Things were great until I noticed my bike was having a difficult time starting. Eventually it wouldn't start at all. It was acting as if the battery had died. Well, I hooked the battery up to a charging unit I own in hopes of charging the battery. It appeared as if it was working, but not for long. Now, today, I hooked it up the charger to start it, got it started, and noticed something - while the bike was running (in neutral and on it's stand), my headlights were very dim. I even gave the bike a little gas (thinking it would increase the brightness) and nothing. So, I turned on the high beams and sure enough, the bike's engine died. I'm concluding that it's not the battery and that it's the bike's alternator (which I just found out is called the "generator" on motorcycles). I'd hate to spend a bunch of money on a diagnostics when I could simply apply that money towards repair work. HELP!!! And thanks.

Best answer:

Answer by Jay
It is actually referred to as a stator. Three seperate windings which are surrounded by a spinning permenant magnet attatched to the end of the crankshaft.

Is the battery connections tight? Sounds stupid, but check it. You may be suprised.

A quick, easy and basic test is with the headlamp set on bright, it should become brighter as you rev the bike from idle to 4K. Shine it against a wall in dim light, the change should be very noticeable.

Bear in mind that todays batteries are crap as well, so it may very well be a bad battery. Regardless or how new it is. Or how much you paid for it.

The proper way is to hook a volt meter to the +/- on the battery. Test with key off, key on, voltage drop when starting and highest reading at idle, then @ 4K rpm's. You should see something like 12.4, 12.1, 10.2, 12.9, and then 13.5 during the previous mentioned testing stages. Any failure for the voltage to rise 1.2 volts over static value would indicate a charging failure. A battery voltage drop while of less than 10V would indicate a weak or shot battery.

If the battery is good, given what you have indicated, typical failed components include a bad stator, regulator/rectifier unit, faulty wiring connections, or all three. The permenant magnet almost never is an issue. Check all connections to the reg/rect unit, the stator AND to the battery.

Given the age of your bike, i would stongly suspect either a bad battery or poor connections at the battery terminals.

What do you think? Answer below!