Seems To Be A Charging Issue

[bdholsin]

On my '83 Heritage Special (stock electrical) I seem to be having a charging issue. I measured the voltage at my battery while the engine was running AND at about 3,000 RPM and it is only showing 12.25V in both situations. I've also pulled my brushes and measured them...they are showing 9mm and 10mm. Yeah, they are getting short but aren't down to the minimum 7mm to justify replacement (yet).

I've been using the "search" function and reading a pile of ways to diagnose what the problem is but I'm seriously confused as to what procedures will apply to my '83. I have TCI (not points) so I should be looking at procedures that are written for the later bikes, right?

I have my trusty multi-meter and can muddle through most diagnostic procedures. I just need to be pointed in the right direction. I'm not sure which of the following is could be:
1. Brushes (probably not as they measure "long enough" for the time being).
2. Stator
3. Rotor
4. Regulator or rectifier. This is where I was getting confused. Does my bike have either/both a regulator or rectifier?
5. Something else?

I'm electrically ignorant but infinitely enthusiastic. This is probably a dangerous combination.

Any help is appreciated.

Brock

 

[retiredgentleman]

Your brushes are at the replacement length,so buy some new ones.

A magnetic field is the first thing to check. Do the feeler gauge check.............I like to use a 0.003" gauge,remove the small cover and hold gauge about 3/4" from the rotor nut.

A simple resistance check of the rotor is a easy check. Remove brushes, measure slip ring to slip ring using 200 ohm scale. Use high resistance scale to measure either slip ring to rotor frame.

 

[bdholsin]

Ok, 650 central is open now. I can order brushes.

Magnetic field test...success. Did it several times. Each time I turned the key on the gage slapped up against the rotor nut.

My multi-meter can't reach in far enough to touch the inner slip ring. I had to use a small screwdriver to make contact with the slip ring and then took the reading from the screwdriver to the outer slip ring. I'm getting ~1.1 ohms of resistance. My multi-meter automatically scales so I can't select the 200 ohm scale.

 

[bdholsin]

Update...I removed the brush holder assembly entirely so I could access the inner slip ring directly. Didn't make a difference. I'm still measuring 1.0 ohms of resistance from the inner to outer slip ring.

Slip ring (both inner and outer) to rotor frame (ground) is overload (infinite resistance, right). I'm guessing that means the rotor is not grounding out.

So exactly what does all this mean?

 

[weekendrider]

Time for another rotor.

 

[bdholsin]

Time for another rotor.

Ooooh, major bummer for me.

 

[weekendrider]

Yep. You can get a used one cheaper but better money says rebuilt. Try Custom Rewind. If it helps you probably won't wear the second one out in your life time.

 

[bdholsin]

I was thinking of going with a rotor from 650central when I can come up with the scratch. Shucks, I don't put THAT many miles on the bike.

 

[bdholsin]

Can the rotor be rewound by a shop? I have a local shop that specializes in rewinding starters. I'm guessing if I can get the rotor off they can rewind it for me.

Just thinking "out loud" for now before I run out and drop $$ on a new/rebuilt rotor.

 

[bdholsin]

Don't know where my manners are...thanks for the advice to retiredgentleman and weekendrider. Pretty soon there is going to be a "POP" and a humongous "whoosh" of air as my head comes out of my ass.

 

[bdholsin]

Here is where I stand for now. I ordered brushes and a rotor puller yesterday. Once they get here I'm going to pull the rotor and take it to a local shop and see if they can rewind it. If they can't or have no success then I'll have to break down and get a new/rebuilt rotor from 650central.

I have a plan so let's see if I can adhere to it.

 

[gggGary]

There is a good how to on rewinding these rotors, the details may be helpful even to a shop that can do this. http://650rider.com/index.php?name=Forums&file=viewtopic&t=717
I have heard not so good things about the new Chinese?? ones out there

 

[bdholsin]

Thanks Gary. That is a great link. Gives me another option in case my current plan of action blows up in my face.

 

[retiredgentleman]

www.customrewind.com has been highly recommended for its quality work.

A friend of mine had a bad rotor. He took it to a local "motor rewind" shop. They put it on a hydraulic press incorrectly, and destroyed the rotor frame.