What does this mean? (stator issues)

[Trader]

OK folks, you know I had issues coming back from the IR on my 88 .

I bought a new battery (acid filled...but any port in a storm!) removed a bunch of fuses and made it home ok.

 

Now the Electrics family and me are not the best of friends. I'm not even really positive I'm using the correct settings on the admittedly cheap multimeter I'm using (see pic)

 

I'm going to relate what I've done in detail so perhaps you can tell me what these results actually mean.

 

Fully charged and no load, using the 20 volt setting I get 12.62 across + and - terminals of battery.

 

With no headlight or tail light on (fuse removed) I get 13.1 at idle and 13.9 v at 4000 rpm...again, across the battery terminals

 

The resistance test and the ac voltage test were done with the plug disconnected

 

Doing the resistance test...

My meter has 200 Ohms as the lowest. Crossing the probes reads .7

between the pins got 1.2, 1.1, 1.2 so that means the actual ohms are .5,.4,.5?

From the pins to a good frame ground I got the same readings??????? (I thought it was supposed to be 0=open?)

 

Doing the ac voltage test...my scale is 200 (does that even matter?)

I got 20,21,21.5 at idle

and 65,72,73 at 4000 rpm ( research said should be more like 100-110 v ac)

 

So what I'm thinking is that the stator is working..... just too weakly?

 

Where do I test the rectifier?....or is that even a possible issue with these readings?

Edited August 15, 2013 by Trader

[Flyinfool]

The resistance from any one of the stator wires to ground should not be 0, it should be infinity. Infinity will be the same thing that the ohm meter shows when the leads are not connected to anything.

 

Since your ohm meter is not real accurate, another test you can run is to check voltage from a stator wire to ground with the engine running, RPM does not matter for this test. All 3 should be 0 volts. If you get a reading then either the windings of the stator or one of the stators leads are shorted to ground. A damaged shorted wire can be repaired, if the stator itself is grounded it is toast.

 

Also when you are checking the battery voltage, do a test with everything on the bike turned on. If you do not see that same 13.9 volts at 4,000 rpm then you have a weak charging system.

 

From what you described, It sure sounds like the stator is the culprit.

[Trader]

OK....so if I want to use a stator from my parts bikes...how do I bench test the parts bike stator (not running) to see if it's any good.

[mralex714]

OK....so if I want to use a stator from my parts bikes...how do I bench test the parts bike stator (not running) to see if it's any good.

 

I would get it rewound and then you will know it's condition.

[Flyinfool]

First is a visual check.

If any of the windings are a darker color than the rest It may be a sign of excessive heat.

 

With your ohm meter set on highest ohm scale, check from each wire to the metal part of the stator. The stator has a insulation coating on it so you have to make sure that you are actually getting a good connection to the metal.

 

With your ohm meter set on the lowest scale. check the resistance of each pair of wires. It should be .36 to .48 ohms. Alls 3 pairs should be very close to the same value. That is about as good as you can test with the stator off the bike.

 

I have attached a PDF file of a procedure that I am writing for checking the complete charging system.

Edited August 15, 2013 by Flyinfool

[frankd]

Steve

 

The only tests you can make to a non-running bike stator are to make sure it isn't grounded AND measure all 3wires and make sure the resistances are equal. Look at the plug and make sure it's not burnt.

 

Frank

[jasonm.]

OK folks, you know I had issues coming back from the IR on my 88 .

I bought a new battery (acid filled...but any port in a storm!) removed a bunch of fuses and made it home ok.

 

Now the Electrics family and me are not the best of friends. I'm not even really positive I'm using the correct settings on the admittedly cheap multimeter I'm using (see pic)

 

I'm going to relate what I've done in detail so perhaps you can tell me what these results actually mean.

 

Fully charged and no load, using the 20 volt setting I get 12.62 across + and - terminals of battery.

 

With no headlight or tail light on (fuse removed) I get 13.1 at idle and 13.9 v at 4000 rpm...again, across the battery terminals

 

The resistance test and the ac voltage test were done with the plug disconnected

 

Doing the resistance test...

My meter has 200 Ohms as the lowest. Crossing the probes reads .7

between the pins got 1.2, 1.1, 1.2 so that means the actual ohms are .5,.4,.5?

From the pins to a good frame ground I got the same readings??????? (I thought it was supposed to be 0=open?)

 

Doing the ac voltage test...my scale is 200 (does that even matter?)

I got 20,21,21.5 at idle

and 65,72,73 at 4000 rpm ( research said should be more like 100-110 v ac)

 

So what I'm thinking is that the stator is working..... just too weakly?

 

Where do I test the rectifier?....or is that even a possible issue with these readings?

If you are getting low ohms from WHITE(stator leads) to ground then your stator is shorted to grong, aka - BAD. BUT>>>>you must test all OHM readings with both regulator connections disconnected. This will eliminate any false readings from a BAD regulator. Lasty...put a new battery in the ohm-meter