Question on Rotor replacement

[XS650D]

Got the new puller and removed my Rotor. Ive never really looked at
one of these before. Looks like a big hunk of metal, no visible screws to pull apart!
Other than OHMing it out it looks perfect, nothing looks burned ,rusted or damaged
in any way. What causes these to completely go like that. I had 5.2 OHM reading
last season and now nothing, completely dead. Could running battery voltage over 15 Volts
have cooked it.I did have an issue last season with my original Reg and Rec and replaced them with
solid state units, changed my key switch and went thru the wire harness looking for bad connections.
Is a Rotor basically a big magnet, how does it lose it magnetism ? Are Ricks Rotors superior to Mikes xs
supposably new revised stock? I can get both here in Canada but Ricks is $100 More!

 

[DaveO]

Is a Rotor basically a big magnet, how does it lose it magnetism ?

Yep. Its not a permanent magnet though (as in PMA). Its a big electro-magnet. That is a series of windings wound around a ferro-magnetic core (iron?). When power is applied using the brushes pressing on the copper rings it becomes magnetic. When the power is cut it stops. Don't know if this is an xs650 one but you can see the windings here.

 

[DaveO]

 

[gggGary]

5.2 OHM reading
last season and now nothing, completely dead.

on the back of the plate that holds the slip rings are soldered connections where the windings attach take a good look at those connections. A resolder will require fastidious cleaning first.

 

[XS650D]

The clear glazed coating is so thick u cant see the wire but upon closer inspection
I see some cracks in the coating and it will break off and expose the wire underneath.
Nothin jumping out at me were the break could be and not sure if its worth trying to
take apart and repair a 42 year old electric part. Is Ricks or Mikes unit basically the same
quality from those that have used them as a replacement.

 

[5twins]

Yes, I think excess voltage could fry the rotor. It happened to a local guy a couple years back. I tested his charging output and saw it was too high (15+ volts revved), and I warned him about it. He said the "mechanic" at work told him it was fine. It was, for about 600 miles, then his rotor burned out, lol.

 

[gggGary]

It's not excess voltage per say, rather that the rotor is under load full time heat builds up.

 

[XS650D]

5T, my voltage fluctuated as high as 15.5 Volts last season til I finally figured out and changed all the components.
It would still go as high as 14.8 at certain rpms but mostly stayed in the ballpark of 14.3 to 14.7.
Is that exceptable? Dont want to fry a new unit LOL!

 

[XS650D]

I just changed out all my Gage lights to LED bulbs I just received and have the rear brake light
LED also. Thats probably not helping matters. I recall changing my headlight bulb to LED and
my Volts shot up to 16 Wow!! Reg couldent maintain the voltage and had to pull it.
I have the Chrysler unit everyone on here purchases.

 

[hermanlifer]

Do not get a rotor from MikesXS, they are no good! They are thinner than stock, I wasted 153$ on one in june.

 

[mrtwowheel]

I only have long time experience with Rick's rotors on Honda CB750C's, very similar to the XS650 rotors. If I ever need a XS rotor I will buy one from Rick's. Your new regulator should extend the life of a good rotor, I wouldn't say the same for most reg/rec combos.

Scott

 

[XS650D]

Thx Guys,Ricks it is!

 

[650Skull]

650D.........Some info on suppliers and The rotor in general'
http://www.xs650.com/threads/rewind-your-own-rotor-who-to-buy-from.51991/