BBSHD Knock?

[EJ25]

Hello. So just yesterday my bbshd devolved a slight knock, it only happens when I'm putting strain on the motor like going up a hill on power and it only seems to happen when its warm say after a few kms. I've linked a video of another persons video who has the exact same noise. I've taken the chain off and held my hand firmly against the chainring to simulate load on the motor and have got it to make the noise, so I'm 99% sure it has nothing to do with the drivetrain. the motor has about 3100km on it. Has anyone experience this? any ideas?.
Cheers

 

[ElevenAD]

knocking sound volume does not appear to increase when the camera is placed near the motor, maybe the issue is somewhere at the rear of the bike, maybe cassette/Derailleur?

 

[EJ25]

i would try and get a video but his would be just as good as mine i think. The noise is definitely coming from the motor unfortunately, as i said in the post i pulled the chain off so the motor isn't driving anything but itself and held my hand against the chainring to simulate load and it started making the noise.

 

[AHicks]

If you've isolated the noise to the motor, it sounds to me like it might be time to pull the motor down for some investigating. Best of luck!

 

[ElevenAD]

If its the same pop when you hold the chainring you know its probably a motor gear. note a BBSHD with no chain will make a grinding sound even if there is no issue.

 

[linklemming]

One of my BBSHDs with about 1500 miles is making this exact sound although nowhere near as loud. Its definately coming from the motor.

I will swap another BBSHD likely in a month or two and then diagnose the problem on the removed motor. I havnt researched any potential fixes (I expect bearing slop somewhere to be the issue as this is the same sound when a non ebike bottom bracket has too much slop due to worn bearings. My TSDZ2 also did this when bearing slop got too bad)

 

[tomjasz]

Earlier BBSHD motors have failing rotor shafts.

 

[EJ25]

Cheers for the replies everyone. I'm thinking the same thing as linklemming it being a bearing or something. I have taken the primary gear out if that's the name for it (the gear directly behind the chainring) and visually inspected it and everything around it and all looks completely fine. I bought the motor almost a year ago so I can only assume it a new model. I might start with replacing the bearings. I will report back with the results. Cheers again everyone

 

[linklemming]

My completly premature diagnosis is certainly suspect. While the sounds are typical of what I hear with bad BB bearings (on non-ebike), its usually when I am actually pedaling and I can vary the nature of the sound with pedaling technique. In these cases grabbing the BB axle and pushing/pulling up/down (radial play) usually has revealed bearing slop and the sound has gone away with a BB replacement.

Whats odd with the BBSHD is it does it even if not pedaling and exactly 1 time per revolution even with my feet off the pedals so I suspect the issue could be something else. Comparing to another BBSHD (no knocking) with about 500 miles shows the about the same about of radial play (its close enough that I question if I am really feeling a difference). This play is only on the non drive side (the drive side has no play). Both BBSHDs have the same amount of axial play (in/out) which is very small.

The radial play on the TSDZ2 was on the drive side and was horrendous (probably 1/16 inch). The noise on the TSDZ2 only happened when pedaling but that bike had no throttle.