1982 XS650SH charging problems

Darp · New Member Joined: Nov 26, 2005 Posts: 1

I need some help and I am sure someone has run into this problem before. My 1982 XS650SH battery keeps going dead. I have put an Ohm meter to the rotor rings (I removed the brushes) and it reads 2.1- 2.3 ohms, rings to rotor readings are infinite. Is the rotor bad? I had put in new brushes and I have checked the wiring, think ing that was it, it wasn't. I also cleaned all of the ground connections and checked the fuse box, all seem ok.

Am I headed in the right direction?

Thanks,

Darp

justjeep1n · New Member Joined: Nov 19, 2005 Posts: 2

I had the same problem with my bike. I followed the steps in the manual and couldn't issolate it 100%. I got the stator tested for free at an electrical shop and it was good. They couldn't test the rotor so I just ordered a new one and it seems to have fixed the problem. Don't forget to test the voltage regulator, I think that that is in the manual. They got a lot of good posts in here, how to troubleshoot, a guy who rewired his rotor, and I just got a reply on replacing the charging system using a BMW part wich is supposed to supply more power.

kd4eqt

Sounds like the windings in the rotor are shorted somewhere in the middle. This effectively shortens the length of wire and reduces the resitance. This also reduces the amount of field magnetism that is generated so your alternator doesn't generate the correct voltage. This is what happened to mine, and being the type of person that cannot stand to pay for something I can fix, I tore into it and rewound it with new wire. I would not recommend this for the faint at heart because you can easily ruin a $50.00 core and have to pay full price for a replacement.
You should be reading somewhere above 5 ohms between the 2 rings. This measures the resistance from one end of the winding to the other. I disassembled my rotor, being expecially careful with the contact plate. If you look at the face of the plate there are several circles which are actually where the screws are. You'll have to dig out the epoxy that covers these and after desoldering the 2 wires connecting the winding to that plate it can be removed. Measure the overall thickness of the rotor and record this somewhere so you'll be able to get it back to the right thickness once reassembled. If not it will rub on the stator housing. Next the assembly has to be pressed apart using a hydraulic press. Be carefull on where you hold the bottom half as the triangular fins will bend if you put enough force on them and then you have a problem. The two halves are splined onto the shaft and one end will press off. Doesn't matter which one. I would scribe a mark so that the halves will go back together at the same point. It will look like a mess because the wire is potted and will not come out as a nice coil. By the way this is the point of no return!! Once everything is apart and you have pulled all of the wire out, bead blast the two halves to remove all of the epoxy. My rotor had 325 feet of 20AWG magnet wire. This can be found at motor shops that do their own rewinding or do a search for magnet wire. I found some online for $15.00 for a pound. One pound is a graciuos plenty to do one rotor. If you look up the resistance per foot this should give just over 5 ohms total. You'll have to fabricate a form from some cardboard or pvc tubing or such and rewind a coil as neat as possible. I used a PVC pipe and some flat plastic epoxied to the ends and then broke apart once it was wound. If it's not neat and tight you won't get the whole amount in the coil. Measure the ID and OD of the space for the coil and build the form based on this. Once I had the coil wound I smeared some epoxy on the coil to hold everything together. Once it was dry I wrapped mine with electrical tape and reinstalled and pressed the two halves back together. Once I attached the contact plate and made sure that it indeed did charge correctly I removed the rotor and used epoxy to seal everything up. Be careful to keep the epoxy spread out so that it doesn't effect the balance too much.
I haven't put very many miles on mine since this fix but all looks good so far. Check out the pictures in my gallery, www.650rider.com/coppe...m=101.html , I have a couple showing the new coil and completed rotor.
Good luck if you try rewinding yours. Atleast I can tell you that it is possible.

Tony

xs650mike

Sounds like you've been steered in the right direction on repairing your charging system. The only things I would add is to go through all of the plug connectors and make sure they are bright and clean and that the fuse boxes are notorious since the fuse clips become brittle with age, they may look OK but will break if you look at them wrong. BTW, an XS650SH Special is a 1981 model year bike though it may say 1982 on your registration if that was the year it was first sold. It may affect parts ordering so you should be aware of that. The '82 is called an XS650SJ "Heritage".

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