Strange Bafang Max M400 Mid Drive Noise - dying motor?

Letterman

10 mW
Joined
Mar 2, 2020
Messages
22
Hi.
I have a 250W Bafang Max that’s recently developed a clicking noise. Sounds a bit like a ratchet or back pedaling but under load.

I’ll check all the bolts again, but I’m wondering if there are any service/repair instructions and drawings of the interior of the motor?
There seems to be lots of info for the BBSHD but I haven’t found anything for the Max.
I can’t even open the internal motor cover at the moment, I think the screws have been glued in with permanent loctite.

Thanks for your help.
 
Hi,

My Bafang M400 Max drive has started making a strange whirring noise (not the electrical hum that I’m used to). I first thought it was the chain, but it isn’t. The noise only appears when the motor has warmed up. When the motor is turned off and I’m pedaling without assistance, there is no noise.

Below is a link to a sound recording I have made of the noise. Please excuse the background noises and wind I did the best I could):
https://sndup.net/7d7p

Does anyone want to have a guess at what this likely points to and how to fix it?

Thank you!
 
I'm not sure about the noise but in many or most cases a problem with the hall sensors is responsible for a strange sound. This is a common problem and could also be related to heat. You'll find many information about broken hall sensor online
 
Hi,

My Bafang M400 Max drive has started making a strange whirring noise (not the electrical hum that I’m used to). I first thought it was the chain, but it isn’t. The noise only appears when the motor has warmed up. When the motor is turned off and I’m pedaling without assistance, there is no noise.

Below is a link to a sound recording I have made of the noise. Please excuse the background noises and wind I did the best I could):

Does anyone want to have a guess at what this likely points to and how to fix it?

Thank you

Hi.
I have a 250W Bafang Max that’s recently developed a clicking noise. Sounds a bit like a ratchet or back pedaling but under load.

I’ll check all the bolts again, but I’m wondering if there are any service/repair instructions and drawings of the interior of the motor?
There seems to be lots of info for the BBSHD but I haven’t found anything for the Max.
I can’t even open the internal motor cover at the moment, I think the screws have been glued in with permanent loctite.

Thanks for your help.
Please give an update if you're still there. I'm thinking, clutch, nylon gear or mabe the axle with torque sensor.
 
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