ErikDK

We found the culprit: Severe rust in the electric motor's rotor and stator:

Help. I convinced my good friend to buy a Kalkhoff pedelec with a noisy Bosch Gen2 Active Line motor, to get him back into riding a bike 8 km's each way to work. He had a really bad experience with with his electric Brompton, which he sold after waiting for ages for spares. I was convinced that buying a service kit, replacing the motor cover plate including som gears and bearing, would solve the problem. Our hope dropped, when we openend up the motor and everything lloked fine, but we carried on, and weren't supprised, when they noise was barely reduced. I will descrbe the noise as a scraping noise, akin to a chain scraping agains a dented chain guard, but it's not that. The noise comes as soon as the motor starts pulling. My friend is really strained for cash, and I feel bad for tricking him into buying the bike. He loves the ride, because it's a large framed one, and he has long legs, and it fits him perfectly. It looks fine, but not new, and he paid the equivalent of £335 for it, and £165 (wasted) for the service kit. What can cause the noise?