Bosch CX cutting out intermittently

[EebStrider]

I’ve now done 2000 miles on the bike, and in the last couple of days, when in eMtb, going up steep hills, the motor shuts off and comes back on quickly. Which does wonders for my momentum.

I've checked that the magnet is secure, which it is, so does anyone have any ideas whats causing this? And how to fix it?

 

[EebStrider]

Just mine then?

 

[Akiwi]

The only thing I could think of was the magnet. I had a similar thing and just fiddled with the magnet and it went away.

 

[EebStrider]

The only thing I could think of was the magnet. I had a similar thing and just fiddled with the magnet and it went away.

Yep, it was the magnet! It was about 2mm out.

 

[miguepram]

Were your cuts like this? My orbea has been doing this for a while, especially on steep slopes. I was going to take the bike to the store but now that you've said about the magnet, maybe that's the problem.

 

[Akiwi]

That's how mine sounded, and my speedo was going haywire. i.e. wasn't staying constant.

 

[EebStrider]

It turns out it was the speed sensor on mine, plus the motor was full of mud and water, which didn't help!

 

[miguepram]

This is how my magnet is positioned. I see it perfectly in line with the sensor. Now I am a bit puzzled because if the failure does not come from there I do not know where it could be, and I am afraid of taking it to the store. I think they will begin to disassemble and do tests without having any idea where the failure comes from ...

 

[EebStrider]

Have you taken the cover off the motor, and cleaned out any dirt or water that may be in there? Mine fills with mud and sludge regularly, so once a week I take the sump guard off and clean it all out. It’s a pretty crap design tbh, considering these bikes are made to go off road all the time.