sjhrlogo.gif (3636 bytes)   Electrical Troubleshooting Tests

 By Doc
 
These electrical troubleshooting tests apply to all stock Harley-Davidson charging systems from shovels to twin cams. This does not apply to magneto type ignitions without batteries. If you have any questions, contact Doc at kvella@lexco.com.

1) Battery Specifications:

Voltage
% Charged
Hours charge time required
12.8 – 13.0v
100%
None
12.5 – 12.8v
75%
3 – 5 hours
12.0 – 12.5v
50%
4 – 7 hours
11.5 – 12.0v
25%
At least 10 hours (Verify state of charge)
11.5 or less
0%
20 hours

2) Regulator inspection:
The regulator base must have a clean, tight connection for proper grounding. Check by using an ohmmeter with one lead on a known good ground, such as a battery cable, and the other on the regulator base.

3) Regulator Bleed Test:
Be sure regulator is connected to battery. Unplug regulator connector at engine crankcase. Use a trouble light and touch one probe to a known good ground and the other to the regulator pins, one at a time. If the light glows, replace regulator.

4) Milliamp Draw Test:
Be sure accessories are not wired so they stay on at all times. Check for this by connecting an ammeter between negative battery cable and battery terminal. With ignition switch and all lights off, there should be no more than three milliamps current. Note: An excessively dirty battery can cause a static surface drain.

5) Total Current Draw Test:
If the battery runs down during use, the current draw of the motorcycle components and accessories may exceed output of the charging system. To check for this condition, place a load tester induction pickup or current probe pickup over negative battery cable. Disconnect the regulator from the stator at the connector on the crankcase and start the motorcycle. With the ignition and all continuously running lights and accessories turned on (headlight on high-beam), read the total current draw. Compare this reading to the reading obtained from the Current and Voltage Output Test. The current output should exceed current draw by 3.5 amps minimum. If not, there may be too many accessories for the charging system to handle. Reconnect regulator after test.

6) Current Output Test:
a) Connect load tester negative and positive leads to battery terminals and place load tester induction pickup over positive cable between circuit breaker and regulator (dc output cable)
b) Run the engine at 3000 rpm and increase the load as required to obtain a constant 13.0 volts. The current output should be 26-32 amperes. Make note of measurement.

7) Voltage Output Test:
After removing the load, read the load tester voltage meter. Voltage to the battery must not be more than 15 volts. If voltage is higher, regulator is not functioning properly or connections are loose or dirty. Do not leave any load switch on for more than 20 seconds or overheating and tester damage are possible.

8) Stator Check:
a) To check for grounded stator, turn off ignition and disconnect the regulator from the stator at the terminal in the crankcase.
b) Connect and ohmmeter on RX1 scale between crankcase and either stator socket. There should be no continuity across either test points. Any other reading indicates a grounded stator which must be replaced.
c) Check the resistance using an ohmmeter set on the RX1 scale. Resistance should be 0.1 – 0.2 ohms across the stator socket pins. If the resistance is lower, the stator is damaged and must be replaced.

9) AC Output Check:
To test AC output, disconnect the regulator and connect an AC voltmeter across both stator sockets. Run the engine at 2000 rpm. The AC output should be between 32-40 volts AC (16-20 per 1000 rpm). If the output is below specifications, charging problem could be a faulty rotor or stator.

10) System Check:
· Accessories on for long periods when bike is parked and not running.
· Accessories on when bike is ridden very slowly for long periods.
· Battery self-discharge and/or accessory draw because bike was not ridden for a long period.

 

    
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Last modified: June 9, 2005