I've had a few of the servo motors open, and all the feedback sensor is, is a 5k trim pot. I think one rotation = 0=>5k. It has no end stops (so you can turn the thing as many times as your want either direction), and just goes through the resistance range.

so say 5k Ohm = fully openRC valve feedback. Some numpty has stuffed around with the trim pot and it's set to 5k Ohm. You install the servo motor, assuming all is good, and have the RC valve closed.

When you turn the bike on, feedback says fully open, actual position is fully closed, motor tries to drive feedback (and valve) to closed position. Since valve is actually closed, motor is pushing hard, draws extra current and either throws a tooth off the gearbox cog or pops a PGM.


The servo motor is actually a little 280 sized motor, I haven't had much luck finding out what sort of current draw those things have.