Hi Jan,
The only maintenance that should be required on the MP1 would be re-tensioning of the spokes if they have worked loose over time.
The only moving part which can suffer from mechanical wear is the ball bearings, but these are usually sealed and are therefore effectively maintenance free.
Making sure you wheel is kept dry after use (and during storage) is the best way to ensure a long and trouble-free life. Failure to do this can result in internal corrosion within the motor which can damage the stator laminations or cause a short in the windings if their insulated coating becomes badly corroded.
Alan
