When cold, starter will turn engine over about twice and then disengage. Sometimes when pressing the starter button, the starter just spins. After the engine is warm, two spins will start it. Battery is fully charged. Relay, solenoid and spark plugs are fairly new. Starter was disassembled and cleaned. Brushes are a little worn. Cables are clean and tight. New points and condenser. Spark is good, and with plugs removed the starter will keep turning the engine over. Thanks for any suggestions.

 

The most common cause for this symptom is a weak battery. The battery must pass three tests to be declared good - it must be able to take a charge, hold the charge under a load, and hold the charge over time. This procedure may help...

[SIZE="3"]1. Fully charge battery.[/SIZE]

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.

[SIZE="3"]2A. Cell test battery [not for maintenance-free batteries].[/SIZE]

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.

[SIZE="3"]2B. Load test battery.[/SIZE]

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.

[SIZE="2"]Bring the battery up to full charge again before proceeding.[/SIZE]

[SIZE="3"]3A. Current Drain Test #1[/SIZE]

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.

[SIZE="3"]3B. Current Drain Test #2[/SIZE]

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.

[SIZE="3"]3C. Battery Cables Test[/SIZE]

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.

[SIZE="3"]4. Charging System Test[/SIZE]

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.

more...

 

Here is a bench test for the solenoid. Unfortunately you do have to uninstall it to do this test. Uninstalling the solenoid can be tedious

Please let us know how you make out with these tests

 

I purchased a Battery Tender, and performed all the above tests with good results. Also removed the solenoid and it passed all 3 tests.
So I think I need to look for the problem in the Starter Drive Unit. Thanks for the suggestions Mick.

 

I am stumped for now but will think on this some more. In the meantime here is a procedure that will allow you to systematically check out the entire electrical system of the motorcycle. This can be tedious - I did it over a period of a couple of days...

Voltage Drop Testing will identify circuits that have bad connections and other problems that need to be fixed. By doing it you will become very familiar with the electrical system of your bike. The details, mainly in the headlight area, are different for different years of Sportsters and for bikes that have had the wire system messed with, but the process itself is the same.

VDT is more accurate than simple continuity testing. If a wire is shredded down to a few strands or if a circuit has a weak connection, the problem will not show up with continuity testing. With VDT it should show up.

We can readily test the circuits from the start button to the start relay, from the relay to the solenoid and from the solenoid to the starter motor only while cranking the engine. These are covered in another Sticky note on ...
Start System Testing.
http://xlforum.net/forums/showthread.php?t=1610248

The best tool is a voltmeter or a multimeter. These usually come with two pointer leads which is not the best setup for VDT. Better is to have a pointer for the +ve lead and an aligator clip for the negative. I cut the pointer off the black lead and replaced it with a clip using a touch of solder. The solder is better than a simple crimp.

At various points during this process you will need to remove the seat, undo the ignition key assembly, remove the headlight from the bucket, remove the rear fender, open the handlebar switches, etc.

Before doing this test do the load test for the battery and the amps test for the generator. Both of these are given in the Sticky note ...
Charging System Checkout .
http://xlforum.net/forums/showthread.php?t=39146

This procedure is done with the engine not running. Begin by measuring the voltage across the two battery terminals; write this down.

Then leave the -ve lead firmly attached to the -ve battery terminal, proceed thru the wire harness attaching the +ve lead to each point as follows, and compare the voltage at each point with that found at the battery +ve. Write down each result. It would be useful to print this procedure, then write down the results on this page.

Begin with the ignition key off ...

1. cable to the solenoid short stud - measure the voltage at the stud
2. wire to the input side of the MAIN circuit breaker - measure the voltage at the input side of the cb
3. output side of circuit breaker
4. circuit to the ignition switch B terminal
5. circuit to the starter relay

Note: all of the above circuits are hot with the ignition key off. It is important that there be no current/voltage leakage in any of them, and that each connection point be protected from accidental short circuits.

Now turn the ignition key to the the first key click; this activates the IGN and ACC circuit breakers ...

1. test at ignition switch IG terminal
2. input side of IGN circuit breaker
3. output side of IGN circuit breaker
4. The gray wire from the IGN cb runs thru the headlite bucket to the RUN switch, and from there a white wire runs to the start button and to the ignition coil. Rather than dismantle the handlebar switch, test the white wire at the ignition coil. If a problem is detected then test at the headlite bucket connector and if necessary at the handlebar switches.

ACC Circuit Breaker ...

1. The ACC cb is fed from the IGN cb by way of the copper bar. Test both the input and output sides of the ACC cb
2. Two orange wires exit the ACC cb. One goes to the rear stoplight switch so that is the next test point
3. The other orange wire goes into the headlite bucket to a connector that has 5 orange wires coming out of it; test by inserting the +ve pointer lead from the meter into each of these six places. The 5 output wires go ...

[i] thru the diode, then into three spots in the 12-wire connector inside the headlite bucket, and thru that connector to black wires to the oil lamp & gen lamps, and on newer models to the electronic tach: the oil & gen lamps and tach would be tedious to access but the wires can be tested at that 12-wire connector inside the headlite bucket
[ii] to turn signal flasher in the headlite bucket: test at the flasher. The two green wires exiting the flasher run to the left and right turn signal buttons, then by brown, green and gray wires to the turn signal lights. These circuits are difficult to test as the current is being turned off and on by the flasher. To test, remove the two wires from the flasher, temporarily join them together, and test at the turn signal bulb sockets. If a problem is found test at the switches and headlite bucket connectors.
[iii] to front stop light switch: remove the tail light lens & bulb and test at the bulb socket; test within the switch housing if a problem is found
[iv] to the horn switch: test at the horn connection; test within the switch housing if a problem is found
[v] loops back into connector itself to service four free spots in the connector: was tested just above at #3

Turn the ignition key to the second click; this activates the LIGHTS cb ...

1. test at the ignition switch L terminal
2. test both the input and output sides of the LIGHTS cb
3. there are two blue wires coming out of the lights cb. One goes to the rear wire harness connector under the seat, the other goes to a 12-wire connector between the inside and outside of the headlite bucket to service the speedo and tach lights
4. test both sides of the rear wire harness connector
5. remove the tail light lens and bulb, and test at the bulb socket
6. test at the 12-wire connector by inserting the +ve probe of the meter

 

If you are hearing a grinding sound it is the Bendix (starter clutch)

 

Have you tried starting it with a jumpstarter or another vehicle? If it starts with a jump, your battery is dead.

 

A new starter drive gear solved my problem.

 

Nice that you got it sorted out