My b4.1 has been working untill 5 min of running then it starts to cog on the jumps or brakes a little under power. My moter was changed, gears diff axles and its not that, battery i tried 3. I changed the sensor cable but I am wondering if its the esc? PLease help out.

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Do you have another esc you could test it with? Friends with sensored sec's? Try using theirs for a little while to see if it still happens.

I have a Nosram Pearl Version 2 (Same speedo).
That is doing exactly the same. I have tried 3 sensor cables, 2 capacitors, new wiring and switch.

The next thing to try is a cap on the receiver and then update the firmware.

Mark