Problem with mid-drive motor?

[ausGeoff]

I have a 250W Bafang 36 volt G340 mid-drive motor on my trike,
with Shimano Nexus hub gears and a rear differential.

Potential problem...

Recently this has developed: When at top dead centre of each
crank arm's travel—just before its downwards power stroke
starts, there's a slight "jerk" forward, and a little metallic "click"
as the arm continues its travel. It feels similar to when a gear's
missing a tooth. It happens when the pedals are under a normal
load, and it happens all the time at the same point on the pedal
stroke, regardless of which gear I'm in at the time.

I've ensured the crank arms are torqued up, and I can't think of
anything else to check—at least externally to the motor.

Should I take off the motor's cover, and have a look inside the
housing? Unfortunately, living in a remote rural locale, I don't
have any access to any local bike shop, and I can't fit the trike
in the rear of our SUV.

Any thoughts appreciated .

 

[JGcycle]

It might be a bad pedal bearing.

 

[zbikeman]

Also confirm that your pedals are appropriately torqued to the crankarms.

Loose pedals can cause clicks and other noises.

 

[stompandgo]

Good suggestions. Also, jack up the rear and spin the cranks by hand to see if it goes away.

 

[dodgeman]

I had a similar click in mine. They put new pedals on and a new front chain ring. That fixed it and I’m not sure but I think the chain ring was the problem

 

[ausGeoff]

Thanks muchly for the suggestions chaps. Any thoughts about the
possibility of a stripped internal gear somewhere in the motor drive?
(images not my trike) The planetary gears of the ring gear maybe?

 

[stompandgo]

Or the Nexus.

Always check the simple things first.

 

[PedalUma]

planetary gears

Your motor looks nothing like that photo inside. But some fresh transmission lube can't hurt. As the guy said, There is nothing as smooth as a lubed tranny.

 

[harryS]

I've had pedal bearings wear out. They sound like that, A loose pedal arm will sometimes pop during a pedal stroke. Middrive motors, because they are applying heavy tension on the chain will amplify noises more.

"It feels similar to when a gear's missing a tooth. It happens when the pedals are under a normal load, and it happens all the time at the same point on the pedal stroke, regardless of which gear I'm in at the time."

On the mid drives I've owned, there's no internal gearing between the pedals and chain, It drives the chain gear directly. There is a clutch that allows the motor to spin the chain faster than your pedals, but otherwise those pedals are in sync with the chain. I expect that everything inside is fine. If you want to open it up, that might be a good time to grease it,
.