Starter switch spring broke, creating a dangerous situation on 2000 Dyna. You can turn on the ignition and the starter can activate. It's also not good for the starter because pushing the switch back up after starting it doesn't release the starter as quickly. Grind.
So you buy the new starter switch, which is paired with cut off switch and comes with wiring. $60. Take the spring out of the new switch.
Unscrew cover assembly on the throttle unit. There's just enough slack in the wiring to pull the old switch unit out enough to take out what's left of the old spring and install the new spring. 10 minute job.
I'm guessing this is the same little spring used in the horn and turn signal switches. They should have them at the dealership.