TOPIC:

77 KZ900.  Runs great for 200 miles then runs like shit.  This time I limped home after dropping 2 cylinders (new plugs) and they looked brand new when I got it home.  Measured voltage at coil for 2&3, 8.3 volts.  Coil 1&4 had 8.9 volts.
I have a Dyna-S ignition, new run/stop RH switch, motogadget m-lock, new green dyna coils, new 7mm suppression wires, new blade style fuse holder.
I did the wired george mod and do have an improvement in volts to the coils, but not full battery voltage.  Battery voltage w/ key on, switch in off position is 12.6, and w/ switch in RUN position it is 12.2.  Measured coil voltage and I get 10.5 volts.  

Should I be concerned that I'm not getting 12.2 volts or be happy I have 10.5?
 

Power drop somewhere. What's running voltage?
Steve

With wg mod you should be getting full battery voltage at the coils. You either have a bad connection in your wg mod wiring or a bad relay.
when testing power to coils make sure you are taking the reading from the power wire and the battery neg pole or a bad neg earth will skew your results.

Where did you connect to coils power. In blue box below? I when direct to battery. It’s fused so no concerns. At the starter rely your relying on the battery positive wire. Direct you eliminate another voltage drop. 

disconect the wire for the WG coil that goes to bike coils #87 on the photo below. Power up and test voltage at #30 and #87 to ground to test WG interior contacts.

 

I have #30 going to the starter relay bolt, not direct to battery.  When measured I got same voltage at starter bolt vs battery positive.
Turned key on, with switch in RUN position, 12.07 volts.
Measured #87 to ground and got 11.95 volts.
NOW, I measured power at coils with the negative probe on battery, not negative coil wire.  Measured 11.92 volts.  

So, I think I am good, seems like I was measuring voltage wrong the whole time and should have been grounding to battery post not coil wire if that makes sense.

Thanks guys!

Good. The relay mode has been removed from the mix. Still need to diagnose the drivability issue. Does spark os 2&3 come back if the bike cools off?

Electronic or points ignition? If points are you getting sparks at the points for 2&3. Crappy chinese condensors only seem to last about 12 months.

No points, have Dyna-S.  Changed from points to Dyna about 200 miles ago.

2&3 will come back to life if I'm WOT intermittently.   Usually I baby it back home.

check the timing advancer. 

What in particular am I checking with the timing advancer?

my test light does on and off when I advance it by hand.

That it’s not stuck. I was trying to think of what might present your problem.

if I understand correctly it’s Very peculiar that is will stumble throttle off but it recovers if you go Back WOT. 

Gotcha on the timing advance, thanks. 

Only time to time will it come back on if I got WOT, not all the time. 

Very strange.  Hoping it was a wiring issue and something was getting vibrated loose.