Fun with EVO electrics

[dan williams]

Back with learndings about the electrical system on my EVO after it glitched and cracked some ribs. Thought it was carb but seems it was electric. One interesting insight was how the electrical system finds ground for the spark plug. The other was the revelation that the 300 Ohms called out in the owners manual for the trigger coil might be a wrong value so if you're diagnosing your Stator and the trigger reads 185 Ohms you're probably OK. 

EDIT, fixed some typos

Beta debug.pdf

Edited 13 hours ago by dan williams
typos

[dan williams]

Hmmm looking at closeups of the other connector and I noticed the water seal on the back of the high voltage wire (Red/White) to the coil looks less than perfect.

 

[lemur]

Just a few observations and suggestions; 1) your spark plug does not require or use rectified voltage to operate, AC works just fine to produce a spark.

2) that pickup coil needs to be cleaned and the proximity between the pickup and the spinning magnet needs to be as small as possible without ever physically touching.  That is likely how you 'fixed' the bike when you removed and reinstalled it.  None of those magnet to coil surface interfaces should include rust or metallic debris.

3) the head bolts should provide a solid sparkplug ground.

4) your diagram shows an ignition system with 2 coils, one coil dedicated to spark and the other to 12volt accessories such as LED lights and fan motor.  Your photo appear to show a multi phase stator coil 🤔 you might not have the correct wiring diagram or the schematic displays the stator coils in a curious fashion.

... if the bike runs and you want to test the alternator outputs, best is to use an oscilloscope.

add: my riding partner crushed a small capacitor that is wired up near the headlight and steering stops crushed it. You might want to check that part assuming his EVO is the same as your EVO 

add: the black box module almost certainly adjusts spark advance timing and that is likely where the biggest difference is between the various modules.  ... timing of the spark is almost the only thing that can be adjusted.

Edited 3 hours ago by lemur

[lemur]

Want the scary news, one way for those  parts to collide is the result of excess play in the crankshaft bearings. Grab the crank firmly and see if you can detect any play in the crankshaft bearings or in the taper shaft and and inspect the keyway on the armature to eliminate that as being a problem.