Motor sometimes not engaging on a moustach lundi 27.5 with bosch performance line motor

Question

The issue I'm encountering sounds similar to Riese Muller with Bosch performance CX not engaging immediately - but may be slightly different.

In a little more detail:

The bike usually starts fine, but around one in ten times the motor does not easily engage, making uphill starts very difficult. The motor will engage again after ~0.5 to ~2 full turns of the pedals.

This is most noticeable after meeting a car on a narrow uphill, hopping off the bike and rolling up/down the hill a little to move out the way.

Using the phone app to turn up the power/sensitivity on "turbo" makes the issue even more noticeable. Some uphill starts it will help immediately, but sometimes it makes no sound/effort until having pedaled a few turns.

The issue happens in "turbo", "auto", and other settings. With the motor turned off the motion of the bike pedals as expected (hard to go uphills, no motor engagement).

The bike is generally in good condition, quite new.

The dealer has attempted to fix the issue (replacing motor), but now claims the motor is working as expected.

Is there some way to fix, or diagnose the issue in more detail?

Answer 1

It seems the issue is not fixable.

Bosch and Moustache say I must talk to the bike dealer about the issue. The bike dealer says they've talked to bosch - and the issue is a feature of bosch motors in combination with belt drives.

Sadly, the bosch firmwire is closed, can't be viewed or altered - leaving no avenue of further investigation.

We've ended up returning the bike, an interesting nugget of information from the bike dealer is that they have another customer with the exact same issue.