An AC voltage test is as simple as it gets. Just connect the multi-meter
to the 2 wires coming from the stator. Set the multi-meter to at least
50v ac and start the engine and measure it near 4000 to 6000 rpm.
Really surprised Yamaha didn't have a procedure, but the manual did
specify 2 to 4 amps @5500rpm. Kawasaki's have 3 amp output and
put out 36 to 40 acv.
If you (or anyone else) is interested in using Yamaha's peak voltage
test specs, I have a simple circuit for it. You split your multi-meters
positive wire and add a simple circuit (on a proto board) that converts
the ac voltage to dc and stores it in a capacitor.
The peak voltage tester is great for testing a cdi, or stator for ignition
problems too.
Bill M.
All the manufactures had their own special tests and test equipment.
Honda preferred testing the charging systems amp output to the battery.
Testing DCv at the battery may seem like the obvious charging system test,
but it just creates confusion.
On a motorcycle (if you did not have a manual) an amp load test is
possible. Turn on all the lights, and apply the brake (light). Then measure
the negative amp draw. Then start the engine and measure the negative
amp draw and confirm that there is a positive amperage charging the
battery as you give it throttle.
On watercraft, sometimes the starter motor is a significant current draw.
Test it with a clamp style multi meter. Spec is 50A for a good starter. More
than 50 amps is too high.