Q. My 1992 Kawasaki ZZR600 cuts out in warm weather and won’t turn over with the electric start till it cools down. I can do quite a few miles before it cuts out again. All the ignition lights light up, horn, lights and indicators work.
When it cools down enough to turn over it won’t start until it gets even cooler. Then it starts and runs great again. I’ve removed the thermostat to see if this helps, but it makes no difference.
I checked the battery voltage and got: Before ignition on 11.93 volts; ignition on 11.60 volts; Cranking it over 9.72 volts; tickover 1100 rpm 13.02 volts; 5000 rpm 15.96 volts.
A. Oh dear, 15.96 volts at 5,000rpm or any revs is way too high and sounds like it’s fried/damaged the battery. A good battery in service should read 12.8v and no less than 10v when cranking.
The regulator/rectifier will probably look damaged or smell fried, even if not it is the likely culprit because it should only let 14 to 14.5v through. Check the wiring to the alternator for heat damage too.