Loud Clicking Noise?

[TNC]

One thought that came to my mind was the pawls in the rear hub. I noticed a small click in mine frequently as I start pedaling with the motor on. I don't notice it when doing pedal-only power. The pawls seem to feed that click and feel more through the right crank because that's where the drivetrain is. At first I thought perhaps it was the clutch mechanism in the BBSHD, but the more I checked everything like the crank arm and such, it seemed to come from the hub but transmits down the drivetrain to where it feels like it comes from the motor/cranks. In my case I'm just about positive that's where my clunk/click comes from.

Now, some of this may depend on the rear hub design that each of us have. Mine is a Shimano XT older style with 6-bolt disc rotor mounts. These have what can be described as a fair amount of "play" before engagement compared to some others. These older Shimano hubs are not alone in this. Lots of hubs have some engagement play in them. It's not something as noticeable when I'm doing the pedaling, but the motor brings it out more. Don't know if this is anyone else's issue, but it's something to check.

[Dshue]

Push down on the motor with the bike sitting still. I just had a horrible creak coming from my bottom bracket. It only happened under pedal loading. My motor didn't "feel" loose but if I pushed down really hard I could replicate the creak. I was about 30 miles from home so I had my wife bring the tools I needed to me and on the side of the road I tightened the motor and it went away. Now I need to remove the motor so I can regrease the bb shell and reloctite the nut. I've gone over 500 miles and this is the first time I've had to retighten the motor.
Greasing the motor shaft and/or the bb shell should keep the creaking noise away as well as keep galvanic corrosion at bay. And I use red loctite on the inner locknut to keep it from backing off. Blue loctite is pretty useless for the job, 1) it is a large diameter 2) it's not something that I need to disassemble with any regularity 3) even with red loctite it will eventually loosen on its own.
Also when the triangle mounting plate goes on you want a slight gap between it and the motor mounting holes/spacers. I would say .5mm or .020" is plenty. If the two surfaces are even then there is no preload on the connection. That slight angular preload makes a world of difference.

In my opinion it is very important to keep the motor tight. Especially with an aluminum frame. The teeth on the mounting plate make divots in the bb shell and when the motor loosens those divots get elongated and can no longer serve their intended function.

[Onemorejoltwarden]

Chainwheel bolts tight?
They are M8 10mm and too short for the job. 3mm engaged. 18mm hole on the BBSHD with stock ring.
? quality
Just one of several possibilities. Crank arms, mounts , axle fit, shaft & bearings , pedals, to name a few.