11.32 is a bit low. That voltage should be a red/white wire. The TCI don't likw low voltage. As the voltage drops the TCI starts losing function. No advance, low spark, erratic spark, eventually no spark.
Power comes from the engine stop switch on a red/white wire to the coil and the TCI box. This wire is the one to check for voltage. in your diagram you have the red/white wire marked red.
in your plug the white/black wire is slot one, counting clockwise around the plug, #2 is the red/white wire, #3 is orange, #$ is black/white, #5 is white/red, #6white/green, #7 is black.
#1 is white/black is the wire to the side stand relay, it can be left unhooked.
#2 is red/white battery power in.
#3 is orange, this wire is the ground wire from the coil, turns coil on/off.
#4, #5, #6 are the wires to the pick ups on the stator.
#7 is the ground.
Now when you turn the key on and spin the engine over power flows to the TCI box and coil on the red/white wire. As the engine turns over the magnet in the rotor passes the pick ups. This generates a tiny voltage in the pick ups which is sent to the TCI box. The TCI box uses this voltage to tell the crank position and engine rpms.
The TCI uses these signals to tell when to spark.
The coil gets battery power on the red/white wire, this voltage goes through the primary side of the coil, out the orange wire to the TCI. The TCI turns on the transistor to send the voltage on the orange wire to ground so power can flow. When the TCI gets the right signals from the pick ups it turns the transistor off, stopping power flow, causing the coil the spark.
The path the spark takes is out one plug wire to the plug, jumps the gap to the engine, across the engine to the other plug, jumps the gap to the plug, up the plug wire back to the coil.
There can be several causes of weak spark, fouled plugs, a bad plug wire, bad plug caps, bad coil, low battery power to the coil or TCI.
Your low battery charge maybe it. Once charged recheck voltages at the red/white wire at the TCI and the coil. If this voltage is more than .2 or .3 less than battery voltage you have weak connections somewhere along the red/white wire. Usually in the key switch or engine stop switch. They can both be taken apart and cleaned.
You can, for testing jump straight from battery + to the red/white wire at the coil, Leave the engine stop switch off and kick the engine.
New plugs are a good idea at this point. Pull the plug wires out one side off the bike, plug in the plugs and hold the plugs together, metal to metal. This way you can watch both plugs fire.
On the coil you now have on there did you test the ohms? Both primary and secondary? Primary around 2.5 ohms, secondary around 8-15,000 ohms, Another 10,000 with caps. Infinity to ground. If any of these are to far off your spark maybe weak.
Another thing, if the signal from the pick ups are weak the magnet in the rotor may be weak.
Radio Shack sells a rare earth magnet that works well to fix that. Go to your local Radio Shack get item # 64-1895, $2.19 A two pack of 3/16 rare earth magnets, Stop by somewhere and get some JB Weld. Now take the stator off the bike, just enough to get room to clean off the magnet in the rotor. Place one of the magnets on the rotor magnet. Mark the top with something, White out a magic marker, whatever, this way you will get the magnet on right. Mix up a dab of the JB Weld as directed on the package, lift off the magnet, apply a dab of JB Weld on the rotor magnet, put the maget back on the rotor with your mark out. Let dry.
do a few more checks and let us know.
Leo