performance line CX sounds...'dry'

[SupasafeElectroLumberjack]

Hi folks

I took my bike out yesterday after a 2 or 3 week period of no riding as the weather has been foul.

the motor was making a very loud whirring sound, akin to bearings or gears that are devoid of grease or lubricant- i noted this first when testing the gears in walk mode, but from then on throughout the ride, regardless of effort, speed, mode, etc. Note, I only ever use a garden hose to clean the bike and give most moving parts a jet of GT85 afterwards too.

questions:

1. has anyone else experienced this, what did they do to repair
2. is greasing moving parts in crank/motor assembly something the casual owner can do without voiding warranty- if so, can you link instructions or guides
3. what grease should one use
4. is this a result of sitting damp, or sitting in extreme cold? my bike storage got down to at least freezing recently.

Thanks all!

J

 

[jerry]

None of it will do any good, or make any difference other than masking the grinding sound. Water has corroded the bearings, and going forward, it will get/sound only worse until it sounds like a coffee grinder.
If you're lucky, it's only the main bearing, which is fairly easily replaced by a pro (even some dealer can do it now)

 

[SupasafeElectroLumberjack]

is there any provision in the warranty against this? its just over 6 months old and only had a few hunded miles put onto it.

shameful design if this is the case!

 

[Themightydickster]

It is a shameful design! Definitely under warranty so get it done - later versions had revised seals to stop this constantly happening, check they will fit these later seals. Worth buying a Mudstopper seal, Google it, they can pop that on whilst they are rebuilding the motor as they are already in that area. This goes over the other seals and stops the problem. Leave it alone then, no pressure Washing it that area, no oil squinted in etc. I just carefully pick the dry mud off with an old spoke, no problem since..

 

[Beekeeper]

I wouldn’t put GT85 anywhere near the drive side of the motor. If that were to enter the main motor bearing it would break down the grease which protects the bearing and also break down the tacky grease behind the seal. I’m sure @Bearing Man will correct me if I’m wrong.

 

[Mteam]

is it the gen 4 motor, or the older gen 2 motor?

gt85 is a solvent and shouldnt be sprayed on bearings etc, as stated above it will cause the grease to be washed out, I suspect the gt85 has caused your issue.

 

[Bearing Man]

I wouldn’t put GT85 anywhere near the drive side of the motor. If that were to enter the main motor bearing it would break down the grease which protects the bearing and also break down the tacky grease behind the seal. I’m sure @Bearing Man will correct me if I’m wrong.

Beekeeper is spot on, please don't lubricate from outside, these motors are not designed to have oil inside them and when a bearing is bad, the oil will go straight through into your motor... As the water does too, when the bearing is worn.

 

[SupasafeElectroLumberjack]

Thanks for the advice all. Have contacted my LBS who will get a new motor on warranty. Will also look into getting a mud stopper seal as recommended.

FYI it's a gen 2, I'm told by the LBS that this is a common fault.

 

[Beekeeper]

I wouldn’t put GT85 anywhere near the drive side of the motor. If that were to enter the main motor bearing it would break down the grease which protects the bearing and also break down the tacky grease behind the seal. I’m sure @Bearing Man will correct me if I’m wrong.

Hi @Bearing Man

the drive side motor kit which Bosch do for approx £100, how long do you think they will continue to make this for? 5 years, 10 years. Presumably production will cease as the old Gen 2 becomes more rare. Is it worth buying one now just in case?

 

[Bearing Man]

Hi @Bearing Man

the drive side motor kit which Bosch do for approx £100, how long do you think they will continue to make this for? 5 years, 10 years. Presumably production will cease as the old Gen 2 becomes more rare. Is it worth buying one now just in case?

I am guessing you will probably sell your bike and buy a new one before the 10 years after life term is up. But, if not... you may want to squirrel one away.

 

[folmonty]

@Bearing Man your web site is very well done. Those videos really helped me see what makes these things tick. Have a new bike w/ Bosch CX gen 4. Your complete bearing rebuild was simply outstanding. Seems like water has a way of finding it's way into these? Is there any added precaution that can be taken short of not riding in the wet?

 

[Bearing Man]

@Bearing Man your web site is very well done. Those videos really helped me see what makes these things tick. Have a new bike w/ Bosch CX gen 4. Your complete bearing rebuild was simply outstanding. Seems like water has a way of finding it's way into these? Is there any added precaution that can be taken short of not riding in the wet?

There is currently no extra protection for the Gen 4 motor. but there are already some pretty good seals on this motor. They do need removing and re-greasing from time to time and this will depend on your riding terrain, cleaning habits, weather conditions etc.

 

[Old Mike]

I am guessing you will probably sell your bike and buy a new one before the 10 years after life term is up. But, if not... you may want to squirrel one away.

Ive got a motor in with you now to get fixed.

One that sounds like its starting to go.

And two working motors.

For two bikes. Once i heard the bosch gen 4 had a different casing i bought some spare motors off a guy in germany.

4 motors + Bearing man and the bikes will hopefully outlive me (im old with a f**ked heart)

???

Swapping the motors out is easy - less than an hour once you get the tools and a few swaps under your belt. People talk about these like they're fighter jets. They're not.

 

[Beekeeper]

Ive got a motor in with you now to get fixed.

One that sounds like its starting to go.

And two working motors.

For two bikes. Once i heard the bosch gen 4 had a different casing i bought some spare motors off a guy in germany.

4 motors + Bearing man and the bikes will hopefully outlive me (im old with a f**ked heart)

???

Swapping the motors out is easy - less than an hour once you get the tools and a few swaps under your belt. People talk about these like they're fighter jets. They're not.

haha, the Gen 2 motor is the new Bitcoin!
Finite supply and everyone who owns one wants more of them to stash away. Me included!