Thanks for the motor cover/ingress questions and apologies for the wait - took a week off.
Firstly, we know that this bike is going to get really wet & muddy (in fact we hope it does) and it is designed & warrantied with this in mind. All electrical connections have suitably IP-rated rubber seals, Brose motor connectors are sealed with double O-Rings and as long as all of the plugs/connectors stay fully pushed in when the bike gets wet everything will be fine. We do not recommend unplugging any of the motor connectors unless you absolutely need to, you are more likely to get dirt and moisture inside them in the process. Wash the bike with all connectors fully in place, don’t remove the battery or disconnect the battery connector when washing – for example. (You can wash an eBike with running water or a bucket and sponge, but never with a pressure washer). You should also never block the drain hole underneath the motor deliberately – this is where any water that does get in should drain out.
Secondly, during extensive field-testing on pre-production models we did experience more debris entering this area than expected. For this reason our product team made two small running changes – 1) Adding a fourth bolt to the motor cover (both sides of the cover were redesigned to add this bolt) strengthened the cover from debris entering from below and 2) Adding a shaped sponge to the inside rear of the motor housing reduced ingress of debris from above. Several thousand bikes had already been made when these running changes were made to production – we’ll update this thread when these parts are available for service. It is absolutely fine to use custom-shaped air-filter/skid-plate/moto-cross foam inside the motor cover, just be aware that the motor will get hot (up to 95°C) and for that reason you should avoid anything domestic or adhesive. (Skid-plate foam is designed to stop mud accumulation next to motor-bike engines – you can search for it online).
To answer a handful of rider questions - whilst it may look unsightly to have small leaves or mud inside the motor cover, unless these block the drain hole completely we have no concerns. As mentioned above, we’ve taken steps to reduce the debris that does get inside but we never saw any reliability or performance issues with our test bikes prior to making these running changes. In the meantime we can see riders are increasingly asking questions about basic care/preventative maintenance for eBikes and will gather some best practice to post in the maintenance thread in the near future.
A template using 10mm thick foam is shown below along with fitting instructions.
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1) Remove left crank-arm and motor cover
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2) Place foam between the rear motor mounts
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3) Replace motor cover and torque M4 fasteners to 1Nm
4) Replace left crank-arm and torque to 40Nm