Do I have a bad Starter? Not Starter Solenoid/Relay or Battery

[tomylee24]

Hello everyone, first time poster here.

I recently picked up a 2020 Vitpilen 401 (2,500 miles). Bike had a low-speed drop but nothing major. I’m working through a no-crank issue and could use input. Hoping I’m not missing something simple.

Here’s what I’ve verified so far:

• Two good AGM batteries (220 CCA), both 12.5V & 12.6V resting.
• Batteries tested on other bikes (larger engines) run normal.
• Engine rotates smoothly by hand at the crank without spark plug — no signs of seizure or binding aside from TDC valve pressure

Symptoms:

• When pressing start: single click from solenoid engages fine
• Voltage drop from 12V to 6V at the battery.
• Dash goes blank, fully reboots and fuel pump primes.
• Power and ground cables to starter gets warm immediately and one relay started smoking

Tested:

• Replaced starter solenoid with new OEM unit.
• Bypassed solenoid and electronics and powered starter directly from battery, no engine rotation
• Left the battery main connected to the solenoid to power but removed starter power. Clicked start no voltage drop or ECU reset happens
• Removed starter and bench tested — spins freely when powered.

Grounds found/checked:

• Starter ground
• Ground near rectifier under tail
• Ground near ABS panel
• I am not finding a frame ground shorting with multimeter

At this point, with spark plug out and significant voltage drop, I’m leaning toward a starter motor that fails under load. I have never encountered a starter to fail like this but I've heard of it being possible. All of the fuses are good and relays read 90 ohms.

I know its a single cylinder but is there anything in the gear train or on these engines that could cause this type of high current draw without obvious mechanical binding when rotating by hand like the one way bearing binding?