Start diagnosis of my charging system

[ash13brook]

When I bought my '72, the guy said it had a charging problem. It has electronic ignition - Pamco, I think, he said. I got out my trusty Haynes and was going to start at the beginning, but no regulator or rectifier where it said they should be. Under the right side cover was a new looking 'solid state regulator/rectifier' (ID'd from MikesXS).
The bike runs fine as long as I keep the battery charged.
One thing at a time as I'm from the days of points and condensers. What's my first move?

 

[retiredgentleman]

Use a voltmeter (VOM) to measure battery voltage.

A fully charged battery before stating engine should be 12.5 volts

Start engine and wait a few minutes, at 1200 rpm should be 13.5 volts

Rev engine to 3000 rpm, should be 14.2 to 14.5 volts.

You must have a good battery...............the charging system cannot charge a wornout battery.

http://xs650temp.proboards.com/index.cgi?board=Charging&action=display&thread=3461

 

[Patches]

Lots to do. Retired entleman above me is probably one of the foremost experts on the factory charging system. I have learned a lot by reading his info. Hopefully I get most of these checks right. Most of your answers can be found by using the search function.

Check your rotor to make sure it's good. 4-6 ohms resistance between slip rings

Check your brushes to make sure they are good (most factory brushes are crap).

Check to make sure you are getting 12V to the brown wire.

Check that you are getting roughly 11-11.5v AC from the white wires at idle.

Check to make sure all connections are good.

Curly's wiring guide in the tech section is your new bible. Read it, rereadig it. Memorize it. Love it. Live it.

Good luck with the project!

 

[ash13brook]

Retiredgentleman-
The battery has 12.57 +/- before starting, and at all rpms after starting.
The battery was new when I bought it last Dec. and will start the bike many times from cold. If I put it on the charger , it always comes to a full charge in a short time.
What's next?
Thanks,
Matt
ps I',m in the middle of winterizing boats and household, so I might not respond immediately

 

[Patches]

Did you check everything else that I listed?

Me thinks not.......

I will reiterate: Look up curly's charging guide here on the forum.

We can't help you if you're not willing to help yourself....

 

[ash13brook]

Looking at the pix on the charging system guide in the tech section, the first thing I noticed is the screws holding the brushes on mine are steel, not nylon and I have a solid state rectifier/regulator. I read somewhere that change is for late model only. Clarify?
I'll be taking the stator off to check the rings on the rotor, meanwhile and check the stator.
What do I look for to tell if the brushes are any good?

 

[XSLeo]

The brushes should be at least 1/4 inch long, a better minimum is 3/8 inch.
Some soild state reg/recs are designed to be a direct replacement for the seperate reg and rec, some are not.
I would say yours is, but I can't see it well from here.
If you have a 70-79 bike and want to run the 80 up combo reg/rec then you need to replace the three screws with nylon and a bit of rewiring on the brushes.
On Patches list, item #3 should read battery voltage not 12 volts. If you have less than .2 volts less than battery voltage you have to much resistance in the battery to brown wire circuit. Find the resistance and fix it, often in the key switch itself. Most can be taken apart and the contacts cleaned, bright and shiny is a good thing.
Leo

 

[pamcopete]

1. The first thing you do with any charging system issue is to measure the resistance of the rotor winding from one copper slip ring to the other with the brushes removed. Should be a nominal 5 Ohms. Replace if less than 4 or greater than 7 Ohms.

2. While you have the brushes out, measure them for at least a 3/8" length. Replace if less than 3/8".
3. Start up the engine and use a very fine emery cloth and / or a pencil eraser to clean the copper slip rings.

Most charging problems will be fixed with these steps.

 

[ash13brook]

My regulator/rectifier is the one on this page:

http://www.mikesxs.net/products-30.html#products

Part no. 20-2089

Thanks for everyone's help so far. Got alittle work to do, now.

Matt