ive got an 81 xlh and it isnt keeping the battery charged. the generator is producing about 15v on the armature and about 10v on the field but im only getting about 12v after it passes through the electric regulator and its down to about 11.8v at the battery. these numbers only go up by a volt or 2 when the engine is reved up. Ive tried 2 different regulators and still get the same reading. any suggestions to help fix this would be appreciated. this problem has been stocking me for almost 3 weeks and no one in any local shops knows anything about generators.

 

There are specific tests you can do on the gen. These are in the manual and in my notes, reproduced below. Other tests done arbitrraily will give certain results like you have, but if they are not the standard tests the results cannot be interpreted.

Work thru the following; do not leave out any steps regardless; let us know what are your results. And any results are meaningless if the batt is not known absolutely to be at full charge, as explained in these notes.

IronHead Charging System Checkout

You need a multimeter. The digital ones are best and can be had for less than $10.00. A voltmeter is a multimeter set to measure DC volts. An ammeter is a multimeter set to read DC current in amps. The ohmmeter section of the multimeter will test for continuity. Continuity means that current may flow between the two points.

I find alligator clip probes are much more convenient than pointer probes. Occasionally a pointer probe is better so i have a set of each.

When using a Multimeter, if the object fails a test, repeat the test ensuring that you have good connections with the meter probes, especially to a good ground.


1. Fully charge battery.

It is not good enough to put it on a charger overnight and assume it is fully charged. Some batteries will take 24 hours to fully charge. The way to know for sure is to do a specific gravity test [for liquid filled batteries], or to use an automatic battery charger.

I have heard that you should never use a battery charger greater than 2 amps for any motorcycle; that it is best to use between .75 and 1.5 amps. Best are the automatic chargers such as Battery Minder or Battery Tender.

2A. Cell test battery [not for maintenance-free batteries].

Remove caps from battery cells. Keep the red voltmeter lead on a terminal and insert the black lead progressively into each cell, far enough that it contacts the plates. You should get readings of 2, 4, 6, 8, 10 and 12 volts. If one cell does not contribute its proper 2 volts then that cell is dead and the battery is no good.

2B. Load test battery.

It is said that, with electronic ignition, you should never crank the engine without grounded plugs attached to the wires. For this test you should install an extra set of plugs into the wires and set them onto the top cylinder head fins.

Disconnect both spark plugs. Attach voltmeter leads to the battery terminals. Crank the engine for 10 seconds [no more!]. Observe the meter WHILE cranking. If it goes below 10 volts then the battery is no good. Alternatively you can buy an expensive battery load tester.

Bring the battery up to full charge again before proceeding.

3A. Current Drain Test #1

Disconnect the battery -ve cable from the battery. Connect the ammeter between battery -ve post and the battery cable. It should read .003 amps or less.

3B. Current Drain Test #2

Disconnect the +ve terminal from the battery. Connect an automotive test light between the battery and the cable. If light comes on there is a current draw.

Note: To determine which circuit is faulty disconnect the circuit breakers or remove the fuses one at a time. When the light goes out you know which circuit is the problem.

3C. Battery Cables Test

With voltmeter connected to battery terminals check voltage while cranking. Then with voltmeter on battery cables check voltage while cranking. If voltage drop due to cranking [should not go below 10 volts] is different cables may be bad or there may be corrosion.


Here is another very simple non complex test you can do if you suspect that something is draining your battery when the key is off. This applies to bikes that have no digital instrumentation (like ironheads). Unhook your negative battery terminal. Touch the wire back to the negative battery terminal, there should be no spark when you do. If it arks and sparks (like a downed hydro pole in a rain storm in a horror movie) then something is drawing power when it shouldn't be.

4. Charging System Test

Measure the battery voltage with the bike not running. It should be at least 12.x; preferably it will be 13.x.

Measure the voltage with the bike idling at about 2000 to 3000 RPM. It should be at least 1.0 volts higher than the not-running reading, otherwise the charging system is not charging the battery. It should be at least 13.x, preferably 14.x.

5. Regulator Test

Disconnect the regulator. Connect your ohmmeter to the orange and tan wires. Note the reading. Reverse the connections. Note the reading. One reading should show continuity, the other should show no continuity. If the regulator does not pass this test it is no good. This is the circuit that prevents the reg from draining the batt when the bike sits overnight.

This test only tests one circuit in the regulator, so even if it passes this test it may still be no good. There are other tests of the regulator that require specialized equipment. These tests are in the factory and Clymer manuals. I recommend taking both the reg and the gen to an automotive electric repair shop for testing if needed. Note: these shops usually want to test both parts together.

6. Generator Test #1: Residual Magnetism

Disconnect both the A and F terminal wires. Connect the +ve voltmeter lead to the A and the -ve lead to ground. Run the engine at about 2000 RPM. The meter should read at least 2.0 volts. If the voltage is low polarize the generator and repeat the test. If the generator fails this test it must be disassembled for repair.

7. Generator Test #2: Maximum Output

Remove both the A and F terminal wires. Connect the +ve voltmeter lead to the A and the -ve lead to ground. Run the engine at about 2000 RPM. MOMENTARILY [not longer than 10 seconds] connect a jumper lead from ground to F and read the meter. The meter should read 25 to 30 volts DC. If the generator fails this test it must be disassembled for repair.

8. Here's a good way to bench test your generator:

1. connect a jumper from the "+" battery post to the "A" armature terminal on the gen.
2. Connect a jumper from the "-" battery post to the "F" field terminal of the gen.
3. Now take a third jumper from the "-" battery post and touch it to the case of the gen.

If all is well the generator will run like an electric motor. With the gen gear pointing away from you the rotation is clockwise.

Don't try this with the generator on the bike.

9. Polarizing the Generator

With the generator fully installed in the bike, all connections made, ignition off; connect one end of a jumper wire to the gen A, and momentarily touch the other end to the battery +ve terminal.

Usually [but not always they say], you will get a spark at the battery terminal and a light clunk sound from the gen.

10. Polarizing the Generator - The Complete Story

1. with the gen on the bench
[i] jumper the gen A to batt +ve
[ii] momentarily jumper from gen F to batt -ve

Note: This can be done the other way around,
[i] jumper gen F to the -ve batt
[ii] momentarily jumper gen A to batt +ve

2. with the gen on the bike, wires not connected
[i] jumper from gen F to a good ground
[ii] momentarily jumper from gen A to batt +ve

Note: This technique is preferred over #3 because the good ground is better than relying on grounding the F thru the reg.
Note: As with #1 this can be done the other way around.

3. with the gen on the bike, all wires connected
[i] momentarily jumper gen A to batt +ve

Note: This is technically the same as techniques #1 and #2 as the F is grounded thru the reg.

4. For bikes with a mechanical reg [1959 to 1977]

Momentarily jumper between BAT and GEN on the reg.

Note: this is technically the same as all of the other techniques as BAT is connected to batt +ve and GEN is connected to gen A.

5. For bikes with a Cycle Electric Generator/Regulator

On the Cycle Electric DGV-5000 generators you have to remove the brush cover and touch a wire from the positive terminal of the battery to the positive brush lead of the generator to polarize it. You can't polarize the generator from the external terminals. (One of the terminals is the battery terminal, and the other has an internal diode.)
You have to try pretty hard to reverse the polarity on those generators and they rarely need to be polarized.

For clarification: Cycle Electric does have a voltage regulator (the CE-540) which looks very similar. It will bolt up to a standard Model 65A generator and has external leads which connect externally between the regulator and the generator.
The CE-500 bolts to a Cycle Electric DGV-5000 generator and the regulator is internally wired to the generator.
- With the CE-540 setup the generator can be polarized by running a lead from the battery + to the "A" terminal.
- With the CE-500 you need to polarize the generator at the positive brush lead.

11. Generator Brushes Assembly: Dismantle, Cleaning, Repair

1. The brushes holder and related parts can be dismantled without removing the gen from the bike. This is useful because, in my [limited] experience, if the gen light is coming on then one or both of the brushes is probably sticking. This can be easy to fix.

I am writing this from memory, not while doing it. I think i have the removal process right.

Remove gen end cap. Remove the bracket and brush cover strap. Remove the commutator end cover. There are 3 screws visible. Two just hold the brushes to the brush holder; these do not need to be removed. The third screw attaches a wire from inside the gen to the brush assembly. Remove this screw. Now the brush assembly can be removed.

Usually it is quite dirty in there so at this point i use a spray can of electrical contacts cleaner to clean up the mess.

The brushes will spring out of the brush holder. They must be each longer than 1/2 inch else replace both. Reinstall each temporarily and work them between thumb and finger to see if there is any binding.

To re-install brushes in holder use long twist ties from the kitchen. Pick out the twist ties after the holder is re-installed.

2. To remove the gen from the bike: Disconnect the wires from the A and F terminals; remove the two bolts from the gearcase side; raise the inner end toward the 11:00 o'clock position, lower the outer end toward the 5:00 o'clock position, and remove carefully.

For the rest you really need a manual. The FM is very good. It is usually not necessary to remove the gen drive gear - this requires a gear puller to remove. The rest of the gen dismantles quite easily.

Once opened up you can do more cleaning and inspection; again using the spray can electrical contacts cleaner.

The FM contains a number of tests that you can easily do once it is opened up: field coil test, shorted or open field test, grounded armature test, and open armature test.

The shorted armature test requires special equipment which a shop would have [a growler]. Doing actual repair may require special equipment such as a lathe, and perhaps experienced hands.

 

Here are the factory instructions for testing the generator output.
All that is required is having a zero to 30 amp ammeter and a couple of wire leads. You can get the ammeter at a local auto parts house, as pictured below.........





pg

 

The actual tests on a generator are well beyond most people, simply because of the equipment required. But there are some things to check that are relatively easy.

First, put a full charge on the battery and make sure it is in good shape. An auto parts store may be able to load test the battery for you.

Since you've replaced the regulator, but didn't indicate whether you polarized (flashed the field) generator, start with that procedure (Polarizing generator, below). Then check your regulator output. If it's now OK (14 - 15 VDC at 75F at 2000 rpm), you're done. If not, ...

Pull the end cover and inspect the brushes, commutator, and wiring you can see. If the brushes are worn out (too short), they start bouncing. Every time they lose contact with the commutator an arc occurs. That eats the commutator up, and then even with new brushes things won't work properly.

Minimum brush length is 1/2 inch on the longest side. New brushes must be seated with a brush seating stone so they'll conform with the curvature of the commutator. Alternately, wrap fine sandpaper around the commutator, and stroke the brushes to give the curve-shape. DO NOT use emory cloth, and DO completely clean up any sandpaper & carbon brush residue.

If the commutator is rough or burned-looking, it can be turned down. This requires a lathe or armature turning device, and then the mica insulation between the commutator segments must be undercut. If your commutator is crappy, I'd recommend simply replacing it 'cause few people are equipped or have the knowledge to do this repair correctly.

If the wire insulation is crappy, you can usually sleeve it with heat shrink. But be careful to not use silicone type heat shrink near commutators and slip rings. The stuff off-gases and interferes with the commutation or slip ring process.

If your brushes, commutator, and wiring look OK it's time to actually test the bits and pieces.

Field coils - Remove/insulate the brushes from the commutator. Touch an ohmmeter, set on highest resistance scale) lead to the "F" terminal and the other lead to any unpainted part of the generator frame. You should get a very high ohm reading. If it's low the field coil(s) are grounded or possibly very dirty. (The actual test uses an ammeter and battery, but few people have an ammeter large enough to do this.)

Armature Ground - This requires a "growler", something that no one has except a small generator/motor repair shop. So instead use your ohmmeter, again set on its highest resistance scale. Touch one lead to the armature core, and the other lead to the individual commutator segments. Resistance should be quite high. If not, the armature is grounded. Clean it & test again. If it's still low, replace!

Armature Short - Again calls for a growler. Use your ohmmeter on the lowest resistance scale. Touch one lead to any commutator segment, and move the other to all the other segments. resistance should never be zero, but will vary depending upon the location of the second test lead. Repeat this until you've moved the first test lead all around the commutator segments. That's actually more than needed, but at least it prevents missing a set of armature coils.

Polarizing generator - This should (MUST! just to be sure) be done every time any wire is disconnected from the generator! Connect a jumper to the generator armature terminal. Momentarily touch the other end of the jumper to the + post on the battery. This is also known as "flashing the field", and restores the correct orientation of the magnetic field.

Generator output test - This is a rough test and requires an ammeter of at least 20 (I prefer 30) amps capacity. Radio Shlock is a likely source for a cheap one. Hook the ammeter in series with the positive lead to the battery. Observe correct polarity or the ammeter will be instantly destroyed! Start the engine and operate at 2000 rpm. Ground the generator "F" terminal. Max time for grounding the "F" terminal is 10 seconds; any longer will likely destroy the generator or regulator. Ammeter should read 18 amps minimum. I do not remember what the uncontrolled generator output voltage should be, as I always used this amp test.

Voltage Regulator - At 75 F, the regulator output should be between 14 and 15 volts when engine is 2000 rpm..

 

LOL, got enough info now?

 

thanks guys itll take some time to go through these solutions and figure out which ones ive done already and ill let you know how it goes.

 

might want to make sure the volt.reg is grounded good as well.

 

eh well the thing is, is ive done everything that my harley repair manual says to do if the charging system isnt working right. ive had people tell me that only having 12v at the battery when its running at 2k rpm is what it should be at but how is that suppost to keep it charged? a normal 12v system should be being charged at 13.8 or so. but ive never messed with generators before so i dont have a definitive basis to go off of and neither does anyone else i ask since they havent been used in cars since the 60's. like i stated before the generator is producing 15 to 17 v at high rpms but by the time it goes through the electric regulator its only at like 12.2. ive tried 2 different regulators and have gotten the same results so mostly everything written on here ive tried short of ripping the generator apart. i just dont know what to do now...

 

Is your gen. light on all the time, flickering or does it go off when you rev. motor. I am wondering if your battery is used up and cant take a charge. Load test it and see what you have
. If it is on steady, possibly brushes are stuck. Easy to inspect with gen. still on bike.

 

yea gen light is constant and the battery is brand new and checks out fine