Good morning, Is there an ebike expert out there who could help with a problem please ? I have a Kalkhoff Activity Groove with a front drive motor. Initial power assistance is good & then restart the assistance doesn't return. It will only start again if you virtually come to a halt. My initial thought was that the bottom bracket sensor was at fault. I booked it into my local bike shop who liased with Kalkhoff who supplied a bottom bracket & circuit board. FOC. With these changed the problem still exists. I have tried to get details of wiring to check & also what the motor sensors do but to no avail. The next route looks to be to change the front motor but I am obviously reluctant on cost grounds. Any ideas or advice would be so welcomed. Thanks. Barrie.