new rectifier, relatively new battery, not charging

[Privateer]

High resistance between the stator wires and ground means the stator windings aren't shorted out to ground.  If the stator gets really hot, the insulation can degrade on the coils.  Sometimes this results in really low resistance between stator wires, other times a low resistance between stator wire and ground.  Either is bad.

Something like an ohm.  If it's really low, like 0.2 ohms, it means the stator insulation is shot.  If it's high (like 3 ohms) then one of the coils is open circuit.

Each of the measurements should be approximately the same, too.  Actually this is more important than the actual resistance.

for me, checking the 3 phases of the stator I got 2.0, 1.9, and 1.8

normal?

[H-2 CHARLIE]

 YOU SHOULD SEE 16-20 VOLTS PER WIRE  AT IDEL AND 3000 RPMS IS THREE TIMES THAT.MAX OUTPUT IS 130 VOLTS.....  Another test is Test continuity test is test each yellow wire and ground ,and the second will be continuity test between each yellow wire and each yellow wire . on 3 wire stators make sure you test  continuity between all 3 wires and each other ...... I think you can test with bike off as well .

[Privateer]

 The Desmotimes book I have doesn't really talk about it.

any tutorials on how to replace the stator?

[H-2 CHARLIE]

 im sure you can have it out in a hour or less . PULL THE SIDE COVER , PULL THE STATOR JUST A FEW  BOLTS  AND ITS RUNNING AGAIN USE GREY SEALENT .

[Privateer]

got it all taken apart tonight.  It looks like a chunk of the adhesive(?) holding the magnets on the drum came loose and baked itself on the stator.  A couple of the winds have some black crusty stuff stuck to them that isn't uniform.

While it's all taken apart, anything else I should look for or check out?

[H-2 CHARLIE]

What oil did you use on the long trip ?     use the grey sealent everywhere and around the rubber wire  plug . EASY FIX  Dont strip the bolts i used red lock tight on the stator bolts .

[Privateer]

What oil did you use on the long trip ?     use the grey sealent everywhere and around the rubber wire  plug . EASY FIX  Dont strip the bolts i used red lock tight on the stator bolts .

mobile 1, same oil i've been using for 5 years.

[Privateer]

here's that black crusty stuff on the backside of the old rectifier, if you can see it at the 3:30 position.

[suzyj]

That's where you've fried it.  When your RR was getting really hot, it was pulling too much power from the stator, which in turn has made the stator windings heat up (p=i^2r).  The heat has caused the enamel that the windings are coated in to burn up, causing the black mess.

So now, the stator resistance is low, because a bunch of turns are shorted out where the insulation burned, and the output from the stator isn't adequate.

You can get the stator rewound (or rewind it yourself) for a lot less than the cost of a new replacement.

This is one of the real issues with bike (or any) electronics.  When something goes, other parts often fail soon after because of the damage.  You can often mask the underlying problems, by say putting in a fresh battery, but the problems will be back, and the nice new part that you've put in will likely be stuffed as well.

[H-2 CHARLIE]

 What seems to cause this is a air cooled motor running on a hot day all day untill you cook / burn up the charging system .. really seems cool weather and nites the motor will run forever but on hot summer days = cook your stator .

[Langanobob]

That's where you've fried it.  When your RR was getting really hot, it was pulling too much power from the stator, which in turn has made the stator windings heat up (p=i^2r).  The heat has caused the enamel that the windings are coated in to burn up, causing the black mess.

So now, the stator resistance is low, because a bunch of turns are shorted out where the insulation burned, and the output from the stator isn't adequate.

You can get the stator rewound (or rewind it yourself) for a lot less than the cost of a new replacement.

This is one of the real issues with bike (or any) electronics.  When something goes, other parts often fail soon after because of the damage.  You can often mask the underlying problems, by say putting in a fresh battery, but the problems will be back, and the nice new part that you've put in will likely be stuffed as well.

In this day of digital electronics and surface mount chips,  the appearance of motorcycle stators is always sort of disconcerting, they look to me a lot like something that came out of Thomas Edison's or Nikola Tesla's 19th century laboratories.