Hi all,

Have a 91 ZX600 that is acting up on me.
Tried to search the forums for answers, but got no results.

Bought it used about a year ago, cleaned out and lined the tank, had the carbs rebuilt, replaced the fuel filter, replaced the thermostat and started riding it. All in all it runs really well, starts right up and has plenty of power.

Now it has a cooling down/dying problem when running at highway speeds after about 30 minutes of ride time. Air temperature does not effect it. It can be hot or cold out and it still does it.

Riding down the road at highway speed (60-90 mph) bike is running great and then it starts to loose power, the temperature drops off and it dies out. Roll it off the side of the road, play with the throtle to keep it running for a few minutes, let it warm up and off you go again for a while.

Antifreeze is full and it is a new thermostat.

Could this be a coil issue?

Coils(s) getting hot and cutting out, which causes engine dying out, which in turn lets temperature go down. As engine cools, coils(s) cool and start working again, which allows engine to run correctly and heat back up. Repeat over and over.

Any thoughts would be appreciated.

Thanks,
Mike

 

it does not sound far fetched. ive heard of coils doing that when they heat up and are bad. is there a way to test a coil?

 

Yes there is a way to test the coils but if they are acting up due to temperature, you would have to simulate the same conditions/ temps to test. An easy way to tell is spray water on the exhaust headers to see which cylinders aren't firing. If you have 2 coils (one for 2 cylinders) either 1&4 or 2&3 will be cooler (longer to evaporate) when you spray the water on them. Or use a infrared thermometer. It also could be the pick-up coils on the RH side of the crank. Also check all the grounds and for each coil too; that can cause all kinds of problems.