Noisy Bafang 250 W 24 V motor

[anotherkiwi]

My friend took his Decathlon front hub bike for a short ride in the rain. It developed a lot of noise which he tried to stop by filling the motor with WD40... At this stage I come into the picture.

I did a short test ride and effectively the motor was much noisier than when I picked it up at the supermarket. Yesterday I opened it. The grease is black as tar which not surprising even though this is a very low km bike because of the WD40 that was injected into the motor. There are no obvious mechanical problems.

1. Could water in the electrics be the cause for this rough running? I did try it quite a long time after he initially had the problem so it should have evaporated.

If anyone has any paths to go down I am open to suggestions. First of all plan is to clean out the factory grease, re-grease, assemble and retest.

2. what grease do you recommend?

Cheers

 

[Woosh]

when water gets into the motor, it will mix with grease and dirt into a black sludge. I usually clean and regrease. If the noise does not go away then you may have to replace the 4 ball bearings.
I use Molykote PG-21

list of recommended grease/lubricant used in the Bafang motors at factory:
Bearing grease - Unical Lithium grease No 2.
Plastic gear grease - Unical Aviation Synthetic Grease AG-11.
Metal gear grease (Black)- HCF Lubrications Technology Co Ltd's MG - 2A grease.
Metal gear grease (white) - Unical Polybear Grease BLD 227B.

 

[Nealh]

Does the wheel spin in the axle ok by hand or does it grind.

 

[anotherkiwi]

Does the wheel spin in the axle ok by hand or does it grind.

It spins freely but is a bit noisy.

 

[Deleted member 4366]

Often the noise is caused when the controller loses sync with the motor when there's a hall signal problem. People think that it's a mechanical problem, but it isn't. You have to post a recording of the noise for us to tell.

 

[anotherkiwi]

Often the noise is caused when the controller loses sync with the motor when there's a hall signal problem. People think that it's a mechanical problem, but it isn't. You have to post a recording of the noise for us to tell.

That was one of my fears... Chasing down some grease and getting the motor back together this weekend.

 

[anotherkiwi]

An update: fresh grease fixed the noise.

 

[Mickyroo]

I have a decathlon rear hub and it has a metallic looking grease in it, would this be graphite grease? Any suggestions as to what grease is the best to go for when servicing a geared hub motor ?
cheers.

 

[Nealh]

I use a tub of Castrol moly grease, It's been knocking about for some 40 years as I remember having it when I used to fix my cars.

 

[vfr400]

In theory nylon can absorb organic greases and swell up, but the gears are not plain nylon, so it's probably no problem. To be on the safe side, I'd use red or white lithium grease, which is often what the manufacturers use.