GSM mid drive strange noise

[Nixtoo]

any suggestions? When I turn the cranks there is a noise like something is grating. There is also slight resistance. If I had to guess it would that something needs greasing. I don't feel amazingly confident opening it up?

 

[trex]

like the BBS01, it's quite easy to do. You remove 5 small screws and remover the cover. Email andy@woosh for instructions.

This is the video for the BBS01, greasing the GSM is similar:

 

[Nixtoo]

Thanks trek, great help as always. I've emailed Andy.
Any recommendations on the best type of grease?

 

[trex]

I use this grease for my BBS01. It's a general purpose Lithium moly grease for anything that needs grease. A tube will last easily 5 years.

http://www.ebay.co.uk/itm/CARLUBE-MOLY-GREASE-400g-CARTRIDGE-MULTI-PURPOSE-LITHIUM-MOLYBDENUM-CV-JOINTS/221509942318

 

[Nixtoo]

Ok, so just removed the motor from the bike, which side do I open. If it's the side with the chain ring, how do I remove the chain ring as just unscrewing the four screws didn't work. Attached is a video of the sound.

 

[trex]

you remove first the chain cover. There are 5 small philips crosshead screws on the other side of the chain cover. Remove them.
After that, remove the 5 silver bolts that holds the gearbox cover. Remove the gearbox cover.

 

[Nixtoo]

Excellent thanks, just opened it. Very little grease. It's the two cogs making the noise. Hopefully one of the bike shops in Ambleside will have suitable grease tomorrow.

 

[Nixtoo]

Would this one be ok?
http://www.halfords.com/motoring/engine-oils-fluids/grease/comma-cv-lith-moly-grease-500g

 

[trex]

I usually use black grease for gearbox. If you go to Halfords, ask them for black lithium moly grease.

 

[Nixtoo]

Greased, but still making the same noise.

 

[trex]

nixtoo, I don't know enough to make out what is different from before, sorry. Wait for Andy's reply.

 

[trex]

just a new thought: the grating noise could be caused by sand and dirt getting into the bottom bracket. Can you check?

 

[Kuorider]

I suspect that this unit is similar to the Bewo. Did you grease the internal parts of the hub? Inside the centre of the large gear you will find at least two bearings and two clutches. Fit the chainring and use it to pull off the big gear. Turn this gear over and examine the works. The clutches look like bearings but only allow rotation in one direction. The small centre one is the pedal shaft clutch which allows the motor to 'overtake ' the pedals without driving them , the other allows the forward motion of the bike to de clutch the motor. There should also be a thrust bearing and a shaft bearing . The noise is most probably from one of the clutches running dry. Grease everything,assemble and run the bike to work the grease through all parts. These clutches are not dry units and need greased just like ball bearings.

 

[Nixtoo]

just a new thought: the grating noise could be caused by sand and dirt getting into the bottom bracket. Can you check?

View attachment 14247

The bottom bracket looks like it could have picked up dirt. Is it possible to clean it?

 

[Nixtoo]

I suspect that this unit is similar to the Bewo. Did you grease the internal parts of the hub? Inside the centre of the large gear you will find at least two bearings and two clutches. Fit the chainring and use it to pull off the big gear. Turn this gear over and examine the works. The clutches look like bearings but only allow rotation in one direction. The small centre one is the pedal shaft clutch which allows the motor to 'overtake ' the pedals without driving them , the other allows the forward motion of the bike to de clutch the motor. There should also be a thrust bearing and a shaft bearing . The noise is most probably from one of the clutches running dry. Grease everything,assemble and run the bike to work the grease through all parts. These clutches are not dry units and need greased just like ball bearings.

Thanks, this sounds quite technical. Are there any YouTube videos with walk throughs?

 

[trex]

The bottom bracket looks like it could have picked up dirt. Is it possible to clean it?

yes, I would put the crank back on the chain ring, brush off the dirt and drip a few drops of motor oil around the axle while turning the crank slowly. The oil will seep inside the bottom bracket and wash the dirt out. I keep my fingers crossed that it's just dirt.

 

[Nixtoo]

yes, I would put the crank back on the chain ring, brush off the dirt and drip a few drops of motor oil around the axle while turning the crank slowly. The oil will seep inside the bottom bracket and wash the dirt out. I keep my fingers crossed that it's just dirt.

Will try that in the morning, thanks.

 

[Kuorider]

Take off the motor first, This will allow all the parts to rotate freely by hand and you should be able to 'feel' any problem. With the motor off you can give it a quick spin on the throttle to check for any roughness (it won't turn by hand easily ). Hold it firmly while doing this like you would an electric screwdriver. Clean the motor gear and inspect the tooth surface,it should be mirror like with no pits or marks,as should all others.
Set the motor aside and rotate the big gear each way, hold the axle and repeat, how does it feel? any roughness or noise. Rotate the big gear and tap the reverse side through the motor hole. Use only, repeat only , a plastic faced mallet or a wood block, and pull the chainwheel to assist removal. It should slip off. Don't force or lever anything. This will reveal the innards, don't remove any parts or circlips, just grease anything that moves. If you can't get this far easily you will need help so stop there.
With the gear off, the pedal axle can be rotated both ways by hand. it should run smoothly both ways with no end float. If it is the BB it should be easy to repair but any problem with the big gear assembly beyond greasing you may need workshop help. These are basically simple devices but stripping out the bearings and clutches will need a certain amount of skill. Given the cost of the unit a complete replacement 'big gear' assembly cannot be much. Post some close up pics of the unit as others may be able to help. I did do a video of the Bewo strip but lost it on a corrupted card somehow. I would much prefer these gear units to run in an oil bath as grease gets forced off moving parts and chucked everywhere except where most needed.

 

[trex]

the GSM gearbox is very much like the Bewo's, fairly easy to take apart and re-assemble. Nixtoo's motor is still under warranty, if greasing does not work, I would send it back.

 

[Kuorider]

Good point Trex, best leave it untouched as any work may void the warranty although I guess Woosh would be a bit flexible about this, and any how may wish to see it 'as is' to determine the cause of the problem. I was assuming the unit had seen considerable service.