Dyna green coil test?

My son got himself a 74 kz900, charging system was toast and he totally replaced all of the components and all the lightbulbs were also blown.
Could this over charge on the system have cooked the coils? We used an elcheapo spark tester and found on #2 cyl an nice fat blue spark, #'s 1,3,4 have a small thin white spark (bike would only run on the #2 cyl.) Plug wires test ok and look very clean at the ends and there is 12v getting to the coils. Does anyone know what the test readings should be for the Dyna green coils? And is there anything else that could cause weak spark on 3 cyls?

If the regulator was bad (a common problem), then yes, you can cook coils, boil batteries, fry wiring harnesses and blow the lights...

If you check the coils with a test meter, you should see around 3.3 ohm resistance between the primary (input) side terminals, and roughly 15,000 ohms between the two outputs. If the coils check out OK, that doesn't mean they are necessarily good as some of the issues only show when the coils get hot.

Check the voltage at the battery with the bike running - at idle you should see around 12.5v, as the rpm rise, the voltage should increase and cap between 14v and 15v - if the voltage continues to climb over 15 volts the regulator isn't regulating... it's not uncommon to see 17v or more when the regulators quit.

I guess I need to rephrase. He bought the bike not running, found the charging system toasted and the light bulbs all blown, then he totally replaced the charging system and fixed bad areas of the wiring harness.Fired it up only ran on #2.At first thought it was the dirty carbs,Currently cleaning and rebuilding carbs. Then saw the weak spark on 3 cyls. Could only get it to run on one(#2) cyl. Will check readings on coils this aft and get back. Thanks, Pat