TOPIC:

Hey guys, I've done some research but I'd like some fresh eyes as I'm frustrated. 83 kz550m1. Complete fresh rebuild on carbs and had the valve cover off to check valve lash prior to the issue. It's misfiring for sure.  I have yet to even sync the carbs and adjust air screws but I did do a visual syncing the throttle plates.  When is running and i pull the plug wires off one at a time, cylinders 1 and 4 change the rpm very slightly but I am getting spark.  Plug wires 2 and 3 will kill the engine when pulled off.  I checked cylinder 1 and 2 plugs and 1 is wet while 2 is dry.  With the good spark coming from one coil and the weak coming from the other, I'm thinking I've got a bad coil but resistance measurements are the same on both. And I check for voltage at the coil power and ground with key on and the ones running to the "good" coil have good power but the green wire isn't grounded?  The "bad" coil has battery voltage. So that's backwards off what I thought I would have found.  Any insight would be appreciated

Not sure about the 550 but if it’s anything like the other 4 banger kaws 1&4 and 2&3 are fired on a different coil. Could be a bad cool or bad connection at the coil. 

Hucksawyer wrote:

Hey guys, I've done some research but I'd like some fresh eyes as I'm frustrated. 83 kz550m1. Complete fresh rebuild on carbs and had the valve cover off to check valve lash prior to the issue. It's misfiring for sure.  I have yet to even sync the carbs and adjust air screws but I did do a visual syncing the throttle plates.  When is running and i pull the plug wires off one at a time, cylinders 1 and 4 change the rpm very slightly but I am getting spark.  Plug wires 2 and 3 will kill the engine when pulled off.  I checked cylinder 1 and 2 plugs and 1 is wet while 2 is dry.  With the good spark coming from one coil and the weak coming from the other, I'm thinking I've got a bad coil but resistance measurements are the same on both.

And I check for voltage at the coil power and ground with key on and the ones running to the "good" coil have good power but the green wire isn't grounded?  The "bad" coil has battery voltage. So that's backwards off what I thought I would have found.  Any insight would be appreciated

It's not clear what you are testing here and how? I would suggest you follow the below and let me know what results you get
 

Keep in mind that it may not be your coil.  It might be the exciter that feeds the coils, or the pickup.  If you have spark and fuel I would suspect the exciter.

I did more testing and I am now getting trigger voltage to both coils. Instead of just the one.  I must have a short to ground intermittently, giving me problems.  I'll track that down and get my problem fixed. Thanks

My problem was intermittent also.  It's almost impossible to find.  I gave up and changed out the coils, exciter and pickup for a Dyna setup.  No more problems.

This is interesting. My 76 KZ900 is having this problem. The bike start fine, idles fine. but once the riding starts and RPM's begin to go over 5.000 cyl  One and four start dropping out intermittently. I've changed the One and Four Dyna Coil and checked checked checked for a bad wire and Coil voltage.
I'll try another excitor and see if that cures it. Thank you for the post.