Topic: Do I need a new stator?

[ddrink]

Hi all,

Another new guy, both to forums and motorcycles.  Trying to figure out the charging system on a 71 cb500 in an Amen Savior frame.  I followed the directions listed in the tech library.  All of the number its putting out fall where they should except for the three yellow leads off the stator.  It says they should be greater than 0 but less than 1 ohm.  I'm getting about 1.3 at the harness connection, and about 1.2 right at the stator.  Does this mean I need a new stator?

Thanks

Dan

[TwoTired]

Put your test lead tips together and note your meter display.  Any reading should be subtracted from numbers measured when testing an external device.

Test leads/connectors have resistance, too.

Does that help?

Cheers,

[bryanj]

Never ever had one go down and if one did it wouldnt go exactly the same on all three coils it would only be one pair of leads that gave you a bad reading.

[ddrink]

Thank you for the input, you were right, subtracting the error from the tester put me right where I needed to be.  Next question is, is there a way to test the rotor on these, doesn't appear to much to them.  If there is way to test them, does anyone know how?

[TwoTired]

The rotor is just a lump of shapped ferrous steel magnetized by the field coil when it is energized. 

If it is off the bike (or the field and stator coils are removed) just check to see if a magnet will stick to it.  If so, it can be magnetized and out to work.  Testing for quality of or total permeablity is not easily done with a simple multimeter.

[ddrink]

Well let me cut to the chase and tell you whats going on and what I've done.  The bike is not charging.  I've replaced the battery, and the rectifier.  Neither made a difference.  I tried adjusting the regulator (turning the adjusting screw in) that did nothing.  I tried bypassing the regulator, by grounding out the white wire (I was told this give it max charge) that did nothing.  So that leads me to believe that it must be something in the altenator causing me problem.  I tested the resistance on the field coil, came up with about 5.5 ohms, then pulled the field coil out and hooked it to a battery to make sure it would magnatize, it did.  This leaves me with the stator and rotor, right?

[TwoTired]

The white wire is power to the field coil.  It's already grounded at the other end.  So, grounding the white wire won't make any magnetic field.  What you want to do for testing is to put full twelve volts on it.  This will allow the alternator to put out it's maximum power at any given RPM.  The black wire to the regulator should be 12V, disconnect and bridge the black and white wires together for the test.

Assuming you already have a good, fully charged, battery in the bike you should see the voltage rise above 13.8 v.  A good regulator would reduce the output (by adding resistance to the field coil power) when the voltage at the battery gets above 14.5-15v, so it won't boil off the electrolyte.

Sounds like your regulator or your wiring is suspect.
Cheers,

[ddrink]

I tried jumping the white and black wires off the regulator tonight.  The bike started, but died quickly.  Once it died I could not get it restarted, after hooking the wires back up to the regulator, and when I turned the key on, there was a buzzing coming form the regulator, and it still would not start.  After futher investigation, I noticed I now have no spark.  I ordered a new regulator from Oregon Motorcycle Parts, just to be on the safe side.  Once that gets here, I'm thinking I'm just going to rewire the entire bike.  All of the wires look fine (no cuts and not many splices), but is still a rats nest in the battery box, and I would like to clean it up.  I've been using the wiring diagram from Oldmanhonda.com, is this diagram accurate?

[Mr. Grimm]

Hey, just thought I would throw this in. Are you running any electrical aftermarket devices, halogen/xenon headlight,running lights? Maybe you're just drawing too much current from a another non-stock part? Also Check the main ground for corrosion/rust. It's also possible for a single cell in the battery to short out or dry-up. Hope this helps.

[ddrink]

no, i'm not running anything like that, I did check the ground.  Solved my sprak issue, turns out my brother was "helping" and readjusted my points for me.  After putting a new regulator on, I'm able to get 13.8 volts, but thats holding the rpm's at 6k for about 30sec while it works its way up from about 13.2.  Does this sound about right or do I still have problems?

[TwoTired]

You need to check charging voltages with the battery at full charge.
Charge it disconnected from the bike and put the battery back in circuit.

If those voltages are with a good battery at full charge, you still have a problem as it should peak out at 14.5 or so.

[ddrink]

Before starting the bike, batt was reading 12.2v, I know it should be closer to 12.5, but I wouldnt think it would make that much difference?  I did pull the batt and hooked it back up to the battery tender, I'll have to see what I get tomorrow.

[ddrink]

Ok, I think I need to check the output from my altenator, but I need a little help.  I know I need to test for AC volts, but unsure of what wires to test and what readings I should be getting.  Any help would be appreciated.

[chrometank]

Gday chop,Just another sugestion from left field,My charging system went down hill then got intermittent then stopped charging.  The wires comming off the winding had gotten brittle and broken under the fibreglass outer tube.Out side they looked good ,inside crap .I supose this happens a lot ? Any way i replaced the wires and now every things perfect.