Thanks for the suggestion Matt – I think I’ll try to run a new starter wire tomorrow and see where that takes me. Not sure about the external starter (don’t have one), but that’s probably a good avenue to pursue if the new wire doesn’t fix it.
Seems like your starter is seeing too much load and is disengaging. Pull the spark plug and see if the engine will crank with no compression. If not, you’re looking at some sort of internal engine friction. Try and turn the motor using with a socket wrench on the sprocket nut. If it won’t crank that way you might have assembled the top end incorrectly.
Sounds like you need to charge the battery. I had the same problem along with the start button logic board being bad. When the battery is even a little be below full charge it doesn’t want to start…esp in cold weather. Give it a charge and let me know