Let's look at the spark system;
1. New, properly gapped & correct heat range sparkplugs(most gap is 0.028" to 0.031"). Denso is another brand to try, if you're not happy with NGK.
2. Unscrew the sparkplug caps from the ends of the sparkplug wires & cut about 3/16-1/4' off the end for a better connection.
3. Before re-installing the caps, get a multimeter, and check the built in resistor in them. They should test at 5000 ohms. If bad, replace them, as most Japanese motorcycle shops carry the NGK sparkplug caps.
4. Have you checked the ignition coils input voltage? If not, here's how to do it:
Testing Kawasaki and other brands of Motorcycle Ignition Coils For Input Voltage:
When voltage testing Kawasaki and other brands of Ignition Coils, the following needs to be done:
1. Remove the fuel/gas tank to access the coils.
2. Fully charge the battery.
3. Using a multimeter, set it up for VDC(Volts, Direct Current), range of 20.
4. Turn on the ignition switch and the run/stop switch to “Run”.
5. Put the multimeter’s RED probe on where the red or red/yellow wire goes on the ignition coil.
6. Put the multimeter’s BLACK probe on either the battery Negative(-) post/terminal or a good frame ground.
7. You should be able to see battery voltage at the ignition coil connection, but this depends on the current draw of other items in the same circuit.
8. If the tested voltage is down to 8-9 volts, you probably need to clean the many and various electrical connectors.
9. To check the spark output at the sparkplugs, use Ignition Spark Testers. Instead of grounding the sparkplug with the sparkplug wire attached, looking for a spark. This method puts the IC Igniter and ignition coils at risk of failure due to high currents, and possible internal shorting.
These bikes have a 5000 ohm, non-replaceable resistor in the sparkplug caps. They go bad from heat, vibration and age. New ones are available at most Japanese motorcycle stores, or through Z1 Enterprises, Inc. - Specializing in Vintage Japanese Motorcycle Parts, including New Old Stock & aftermarket parts. Z1 Enterprises, Inc. - Specializing in Vintage Japanese Motorcycle Parts, including New Old Stock & aftermarket parts. | www.z1enterprises.com
is their website.