Motorcycle Repair: Hot coils and battery overcharge, kawasaki kz1000, defective coil

Question
1976 Kaw KZ 900.

I have replaced the seperate rectifer regulator with a single unit.  However I beleve it keeps on burning out and blowing bulbs and overcharging the battery.  The replacement units seem to last one season. Then as is the case right now I start having problems.  I have not blown any bulbs yet but the coils (Dyna)are getting warm.  I beleve bad points could cause the coils to get hot but what about the battery.  I could use your opinon on a solution.

Answer
Hi Colin,

Ignition coils will get wam, even hot due to the resistance of their windings and heat from the engine. This is normal. On the otherhand, a defective coil may become very hot sometimes even cracking its casing.

Ensure all grounds are clean, tight, and in good condition. Use dielectric grease on electrical connectors to prevent corrosion and water shorting. Test altenator output and other tests shown below.

Visit www.electrexusa.com Look at their parts and use their on-line troubleshooting chart (printable). I recommend their electrical parts over OEM parts. Very high quality parts.

Send me an email. I'll return test and repair information files such as the one that follows. (The KZ900 tests are same as KZ1000). My email address is: mshively1@woh.rr.com

Respectfully,
Mark Shively



1977-78 Kawasaki KZ1000 Charging System Troubleshooter


1.) Battery Test (ignition off): Meter Scale: 20V DC, Meter Connections: Red test lead to Positive battery terminal, Black test lead to Negative battery terminal, Specifications: 12V min. No more than 1V drop, If up to spec proceed; if below spec, replace battery and retest.

2.) Battery Test (ignition on) (lights on): Meter Scale: 20V DC, Meter Connections: Red test lead to Positive battery terminal, Black test lead to Negative battery terminal, Specifications: 12V min. No more than 1V drop; If up to spec proceed, if below spec charge or replace battery and retest.

3.) Charging System Test: Meter Scale: 20V DC, Meter Connections: Red test lead to Positive battery terminal, Black test lead to Negative battery terminal, Specifications: 13.6V @ 4000 RPM; If above or below spec proceed to next test, if up to spec-charging system is OK.

4.) Alternator Test: Meter Scale: 120V AC, Meter Connections: Disconnect alternator output leads. Check AC output between all three alternator leads @4000 RPM, Specifications: 62V @ 4000 RPM; If up to spec proceed, if low-replace dyno armature and retest.

5.) Rectifier Test: Meter Scale: R x 1 Ohms, Meter Connections: (Disconnect Rectifier) (1) Connect Black test lead to ground wire from rectifier. With Red meter lead, check each Yellow rectifier lead for resistance. (2)  Connect Red test lead to ground wire from rectifier. With Black meter lead, check each Yellow rectifier lead for resistance. Specifications: Resistance in one direction, very little resistance when test leads are reversed (check service manual for ohm specs). If good proceed, if bad replace rectifier and retest.

6.) Regulator Test: Meter Scale: 12 Amp, Meter Connections: Connect meter in series with battery. Connect Black meter lead to ground, and Red meter lead to Negative terminal of battery. Kick start engine, and recheck meter reading @ 4000 RPM. CAUTION! Do not use electric starter. Specifications: 5.8A @ 4000 RPM; If up to spec proceed, if high or low-replace replace regulator and retest.

7.) Unregulated System Test: Meter Scale: 12 Amp, Meter Connections: (Disconnect regulator from system) Connect meter in series with battery. Connect Black meter lead to ground, and Red meter lead to Negative terminal of battery. Kick start engine, and recheck meter reading @ 4000 RPM. CAUTION! Do not use electric starter. Specifications: 9.5A @ 4000 RPM; If good, test complete. If bad, go back to #1 – Start over.