How do i test if the stator is bad - 2002 Yamaha YZF-R1

You should have a 3 phase charging system. Which means you have 3 leads coming out of the stator. They will usually be yellow or white. If you attach you meter leads from lead 1 to 2 you should usually get around .2 ohms. Then do the same check from 1 to 3 and 2 to 3 Then take one meter lead and connect it to chassis ground while touching all the leads , one at a time. If you get numbers of any sort when you're checking the ground the stator is bad. If not then your regulator. The more common problem with Honda is the regulator. Stators very rarely go bad.

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ENGINE OFF,UNPLUG the regulator, test continuity from each conductor to ground on the stator, if you have continuity STATOR IS SHORTED... if you test voltage OUTPUT at the stator, it should be around ten volts AC! NOT DC! per thousand RPM... THEN use a 12 volt test lite from regulator leads to ground, if ANY light happens at either lead, BAD regulator

If you had your meter in AC VOLTS, and you only got three volts out of the stator, it's bad. Check for a shorted stator but putting your meter in OHMS R X 1. Put one probe on the engine case and then the other to one of the contacts and then to the other. You should read infinite ohms. 12.5 volts is the normal reading of a fully charged battery. I never do the shorted stator test. Why? If the stator is not putting out at least 30 volts at a high idle, it makes no difference if the stator is shorted or what, it needs replacing. That's the way I look at it.

Good Luck
Steve

It could be a bad stator, a bad rectifier or a bad voltage regulator. Don't just jump to the stator unless you do some testing.

This can be one of five things,

1: The coil is bad
2: The cdi is bad
3: The stator
4: The stator pickup
5: Bad plug

Use a spark plug tester on the coil to test for current, if it doesn't have current to the plug work your way backwards toward the stator, testing each item for current in and out.

A Honda stator is tested the same way on or off the bike. You take a voltage meter and check for continuity between all three yellow wires (all combination's). You should not have any continuity between a yellow wire and ground. That is the sign of a good stator. Two yellows do not connect or a yellow grounds the stator is bad.

It's much more likely that its the stator although they do do the odd regulator as well.
Start at the stator first as it is easier to test.
Disconect the stator wires-sometimes behind the front sprocket cover-sometimes further up the wiring loom.
Using a multimeter check for resistance between the yellow wires (3x) comming from the stator cover. Check that none of these wires has conunuity(connection) to earth.
If any/all do you have a burnt out stator- remove the stator cover & inspect- the windings will look burnt & smell bad also.

If the stator tests fine then the reg is most likely the problem.

Hope this helps-
Regards Andrew

the fact that you only get 47 volts indicates the stator has an open, there is nothing else but the stator that causes this low un-regulated voltage reading, all stators are tested the sam no matter what they come out of, car motorcycle, ATV etc.
here is the basic test.

STATOR TESTING.—The stator winding can be tested for opens and grounds after it has been disconnected from the alternator end frame. If the ohmmeter reading is low or the test lamp lights when connected between each pair of stator leads (fig. 2-31), the stator winding is electrically good. A high ohmmeter reading or failure of the test lamp to light when connected from any one of the leads to
the stator frame (fig. 2-32) indicates the windings are not grounded. It is not practical to test the stator for shorts due to the very low resistance of the winding.





Figure 2-32

Start with charging and load testing the battery. Then test the stator, to test the stator on the bottom of the right down tube is the plug that goes from the stator to the voltage regulator. With a multi meter, read the voltage from the stator, I forget the exact values but as you rev the motor the voltage should climb if it dosn't your stator is bad. If the stator is good take a reading again with the motor running at the battery cables, again I forget the exact value but you should have a steady reading at the battery, if it isn't and fluctuates it is bad.