How do you test an alternator ?

[Bugslayer]

Does it have to be off the bike, or is there a way on the bike?

[sandy]

Do you have a volt meter? Commonly called a VOM (volt ohm meter). Measure the "key off" voltage. ~12.2 ---- "key on" = ~12.1 ---- Start bike and slowly rev engine while measuring voltage. It should increase to ~14.2  ----- This should tell if the alt is charging.

BTW: ~ means approximately

[RONNIEB]

What Sandy said

[gordonv]

Ah, but where to measure the voltage at?

I think he is saying positive lead to positive terminal of the battery. Negative can go to any ground, but I would also use the battery terminal.

Like mentioned, this will show if there is power going to the battery.

If the reading doesn't change from ignition key off, and the bike revving at higher RPM, then power is not going to your battery. Then you need to test for power output at the alternator.

Ask again after you get some more information.

[Bugslayer]

Good info..... Thanks!