"2nd dead bosch gen 4 motor not happy

[Bearing Man]

Besides all the other upgraded parts, it looks to me that the “single lip rotary seal” is one of the best solutions.

I now have 2 Bosch CX gen 4 motor sitting on my shelf and one in my bike, that will eventually fail. I feel like I can start becoming a submarine pilot again without the anxiety. (Within reason).

I’ll have to figure out the logistics of shipping a motor across the pond.

Don't worry, we've finished the "how to" video and our partner in the US will have these kits very soon!

 

[arTNC]

I don’t think there’s a silver-bullet that would prevent our motors from failing. The combination(s) of abuse's are endless. Most motor manufacturers have done almost everything they can think of to prevent motor failure. We are essentially the test-monkeys for future motor development on ebikes.

I’d like to stretch the longevity of my motor forever …but that’s unlikely to happen. But there are a few things I can do to help (specifically regarding the Bosch CX Gen4 and probably most ebike motors).

I don’t power wash my bike.
I don’t use detergents or cleaners on my bike.
I try to maintain proper cadence.
I service or replenish the external oils or grease on bearings or seals on most moving parts.
I try to maintain stuff.
I rely on expertise e from Pete or some reviews from Jonesy (or whoever), and some of my own experiences.

And my environment differs from yours. (Heat, cold, debris, mud, water, dust, use or abuse …etc. There’s a list of things to consider.

I don’t think oil-filled motors are the absolute answer. There’s a number of issues that can arise from that type of motor. I’ll still be searching for that silver bullet …but in the meantime , the market and manufacturing will evolve.

Good points. I think my situation will likely be "the ideal" example of how long one of these G4 motors can last. In west Texas and Moab, it's about as dry as you can get, and intentionally and with absolute dedication avoid all water and mud...period. I know you folks in wetter climates don't always have that option, but I did the same thing with my pedal-only MTB's. If my motor dies, it will not be because of moisture.

I do have a VOLspeed tuner on my Rail 7 set to a max of 25.4 mph...which I do not attain except in steep downhills with heavy gravity assist. This tuner does not boost the power to any crazy levels. It has some small dynamic influence, but its biggest benefit is not shutting off the motor in that idiotic 15 mph range. I use appropriate cadence and effort on the cranks, trying not to lug the motor in the wrong gear. The motor case never appears to get hot regardless of the temps or conditions I ride in.

I noticed Bearing Man's question earlier if anyone was hearing a louder whine from their motor at the normal 15.4 mph cutoff. Of course mine doesn't cut off anymore at that point. However, I'm a fairly serious performance motorcycle and automotive guy and have always been very attentive to motor and gear noises, especially changes. I never hear a peep of change out of this motor sound...only a slight variance of natural pitch with rpm. This motor has 800 miles on it now ridden exclusively in real off trails and all in turbo mode. Time will tell.

 

[JGH]

The printed circuit board (PCB) that sits around the crankshaft shows water damage and dirt/mud spots on it. This damage has come from the water and dirt dripping from the crankshaft ingress again. Once cleaned, dried and treated, this PCB actually still worked but was about as close as they come to killing the motor completely.

Does the PCB have any conformal coating at all? Even thought I'd expect something way thicker than conformal coating here.

 

[JGH]

I really don’t know what their motivation is. But that doesn't make sense. And those old Betamax and VHS machines were fully supported by their manufactures, and frankly, just like our Bosch emotors, boy did they need it.

IMO Bosch is trying to increase their profits. But they are not taking sample from Betamax and VHS - they are taking samples from the company doing it best in the world currently - Apple. And sadly Bosch is not the only company which copied this innovation of Apple.
Why sell spares when you can sell whole unit or a newer model.
And that will happen more and more as long as consumers will tolerate that and won't resist.

 

[Weeksy]

And that will happen more and more as long as consumers will tolerate that and won't resist.

But how does this manifest itself for the consumer ? How would they go about not-tolerating it ? THere's only one real option and that's not buying the products, which some seem to not to with say Shimano motor'd bikes or Fazua, but some people still love both of those, some love Brose some hate Brose.
Writing to Bosch and saying "your motors are crap" is going to get straight into the deleted items folder...

So what does the consumer do ?

 

[Bearing Man]

Does the PCB have any conformal coating at all? Even thought I'd expect something way thicker than conformal coating here.

No real conformal coating. But don't forget, manufacturers say that the motor is sealed, so wouldn't need a coating

 

[JGH]

But how does this manifest itself for the consumer ? How would they go about not-tolerating it?

So what does the consumer do ?

1. Don't buy their products. Look for alternatives (and yes, when every manufacturer moves towards this practice - it is hard).
2. Inform othwrs about the issues. Lots of people are not aware. I was not aware of the Bosch issues, but this forum has shown me the light.
3. Follow Right 2 Repair movements.
4. Write to your MPs.

 

[AF1]

No real conformal coating. But don't forget, manufacturers say that the motor is sealed, so wouldn't need a coating

As circuit boards are impossible to buy new, would it not be a good idea whilst in there, to coat them in resin or similar?

I presume your mods are not suitable for the total immersion in the video above where a warm motor is suddenly cooled by a deep puddle or pool and a partial vacuum created which sucks water in?

 

[JGH]

No real conformal coating. But don't forget, manufacturers say that the motor is sealed, so wouldn't need a coating

In your expert opinion - what percentage of motors you have seen/repaired would still be working if there was a proper conformal coating?

Have you ever considered or properly coated the PCB of a repaired motor and if not - why?

 

[JGH]

As circuit boards are impossible to buy new, would it not be a good idea whilst in there, to coat them in resin or similar?

I thought same, but best would be best to coat a motor PCB while it is new and as I read it is hard and risky to disassemble the motors.

Unless there is some way around without disassembly.

 

[Stihldog]

If/when you have water ingress in your motor you have several problems. The wear and tear caused by rust on internal components is one. Water, moisture, humidity is another. Sudden changes in temperature …yet another.

From my experience, coating a pcb with anything makes it almost impossible to repair. Failed connections on soldered points caused from sudden changes in temperatures is only one cause. Corrosion or electrolysis is another. Vibrating …another.

I don’t know of any motor manufacturer who wants a reputation of failing motors. They won’t last long, and shouldn’t last long, in this market.

So they must evolve, improve and repair their past experiences …or do nothing and go away.

 

[AF1]

I thought same, but best would be best to coat a motor PCB while it is new and as I read it is hard and risky to disassemble the motors.

Unless there is some way around without disassembly.

Of course, if coating is the way forward then manufacturers should do it in production. However my point was could @Bearing Man do this when the motor is disassembled?

 

[JGH]

From my experience, coating a pcb with anything makes it almost impossible to repair. Failed connections on soldered points caused from sudden changes in temperatures is only one cause. Corrosion or electrolysis is another. Vibrating …another.

True. Coating PCBs makes them unrepairable. But are PCBs on these motors repairable even without coating? Has anyone seen schematics and repair manual of that PCB? PCB is not modular and even torque sensor is more or less paired to the whole PCB.

Moreover, how many of these PCBs have have killed the motor because of:
a) PCB corroding due to water ingress
b) Vibration, temperature changes, failed connections, etc.

 

[Stihldog]

True. Coating PCBs makes them unrepairable. But are PCBs on these motors repairable even without coating? Has anyone seen schematics and repair manual of that PCB? PCB is not modular and even torque sensor is more or less paired to the whole PCB.

Moreover, how many of these PCBs have have killed the motor because of:
a) PCB corroding due to water ingress
b) Vibration, temperature changes, failed connections, etc.

I completely agree. Repairing pcb’s have been a waste of time and money for the past 40+ years. Diagnostic repair and replacement was the way forward …until that didn’t even make sense.

Now we just buy a newer model. (Motor, TV, phone etc).

 

[Bearing Man]

As circuit boards are impossible to buy new, would it not be a good idea whilst in there, to coat them in resin or similar?

I presume your mods are not suitable for the total immersion in the video above where a warm motor is suddenly cooled by a deep puddle or pool and a partial vacuum created which sucks water in?

It would be a great idea to coat these boards, but in many cases the board is soldered to the motor and would be a nightmare to coat. In other cases (including Gen 4) the motor case is used as cooling for the board, this part could not be coated due to temperature transference and this is the part that often blows. We have been doing these motors a while now and always on the lookout for ways to improve things, but sometimes when we look at logistics, added cost and risk when compared to failures, it's not really feasible.

Our mod probably is very capable of withstanding total emersion and pressure washing. However, the standard bearings with their shields are not. Again, water is not sucked into the motor, it is sucked into the bearings, then the bearings fail, then the water can poor straight into the motor. I

Here's something to consider: Most motors failures are bearing related, if you catch this early, your motor can be repaired by just changing one or two bearings and water should not get into your motor. Therefore, no worry about the PCB. However, If you don't bother, or just keep riding regardless of the horrendous noise and rough feeling through your feet, a repair is going to be very expensive or impossible anyway.

Imagine the crankshaft in place and see if you can spot the issue in the picture below... It's a genuine mystery to some how water ever got into their motor

 

[Bearing Man]

I thought same, but best would be best to coat a motor PCB while it is new and as I read it is hard and risky to disassemble the motors.

Unless there is some way around without disassembly.

Don't worry, it's no riskier to remove the PCB whether its old or new.

What manufacturers should stop doing is fitting PCB at the bottom of the motors!! Yamaha for example have a thick coating on the PCB, but then fit it at the bottom of the motor, in the water! The water then eventually soaks between the board layers and destroys the components from within!

True. Coating PCBs makes them unrepairable. But are PCBs on these motors repairable even without coating? Has anyone seen schematics and repair manual of that PCB? PCB is not modular and even torque sensor is more or less paired to the whole PCB.

Moreover, how many of these PCBs have have killed the motor because of:
a) PCB corroding due to water ingress
b) Vibration, temperature changes, failed connections, etc.

We have reverse engineered several PCB's from different motors and can/do change certain board components.
PCB's in ebikes are killed primarily by water (see Gen 4 bellow), followed by component failure and finally connections.

 

[Gareth]

Here's something to consider: Most motors failures are bearing related, if you catch this early, your motor can be repaired by just changing one or two bearings and water should not get into your motor. Therefore, no worry about the PCB. However, If you don't bother, or just keep riding regardless of the horrendous noise and rough feeling through your feet, a repair is going to be very expensive or impossible anyway.

Indeed. But also a little knowledge helps. I was concerned about my motor. So I took it to a reputable bike shop. A bike shop that happens to sell plenty of emtbs. I had very slight play in my DE bearing, occasional sprag clutch drag and I’d had a few error messages (might have been error 500 or something). They told me my motor was maybe showing signs of wear but was probably good for a few thousand more miles. Nothing to worry about. Same bike shop that told me the motor mount screws should be torqued to 40Nm right enough (I should have known better than to accept that figure – doh!) on a carbon frame.

Anyway, two weeks later my motor died. But I know better now, all three of those symptoms were actually screaming – STOP!

Lots of people are not aware.

Exactly JGH. I learned the hard way.

IMO Bosch is trying to increase their profits.

Continuing to manufacture a product that is unreliable, will fail and is ‘not repairable’ is not a route to increasing profits.

Anyway, it looks like BearingMan may have the answer. That looks like well thought out carefully engineered upgrade. Hopefully, fingers crossed, an upgraded Gen 4 that is now going to last a lot longer. This might even persuade this hopeless addict to buy another ebike knowing that there is now help and maybe a long term future outside of warranty.

If you think about it BearingMan is not only offering another worthwhile upgrade which will bring ebikemotorcentre more business, but may well actually inadvertently help bike shops sell more Bosch powered emtbs cos there’s now a company that can not only fix em but improve them outside of warranty.

And surely ebike motor manufactures must be now fully aware that, at least in some markets, ebike motors in emtbs are not really cutting the mustard. Things can only get better – maybe.

 

[rutger]

i think bosch can also learn a lot in the field of water management in a car they also look where water and sand goes they don't want sensors dirty now at bosch all the water seems to flow via the frame over the engine....... forcing the water to go somewhere else doesn't seem that difficult to me...they do have cooling fins on the engine....why no edges to drain water?

 

[lar1337]

The wait is over! A more comprehensive explanation, reasoning and price will be on our website as soon as I have time. I cannot confirm a price on here as prices change, but in the UK this should be just under £200.00 Please note, the parts are not that expensive, but this motor is extremely time consuming.
View attachment 144527View attachment 144528View attachment 144529View attachment 144530

Any news on an available date for this upgrade?

 

[Bearing Man]

Any news on an available date for this upgrade?

The clue was in the first line of the post Anyway... all available now!

 

[Bearing Man]

We have new standard, new upgraded and reconditioned Bosch Gen 4 motors for sale. I can't put prices on here because here is forever and prices change, but please feel free to email us here: [email protected]

 

[RustyMTB]

Out of curiosity Pete, if I had to replace my Gen 4 motor, would it be plug & play or is work required to pair a different motor to the rest of the system? Sorry if this has been asked before.

 

[Bearing Man]

Out of curiosity Pete, if I had to replace my Gen 4 motor, would it be plug & play or is work required to pair a different motor to the rest of the system? Sorry if this has been asked before.

If your motor is pre Bosch "smart" system, it would be technically 'plug and play' and it would work. However, the wheel circumference would probably need setting along with power modes, lights on or off etc. (provided you don't have e-shift)
If we supplied a replacement, this would all be programmed in before shipping the motor to you.

 

[Stihldog]

Out of curiosity Pete, if I had to replace my Gen 4 motor, would it be plug & play or is work required to pair a different motor to the rest of the system? Sorry if this has been asked before.

I’ve changed a few Bosch CX motors (pre smart) between several bikes to keep things running until minor repairs can be done. Re-programming or pairing was not necessary.(unless wheel circumstance or lightning changes) Basically plug-n-play.

It’s also a good time to smooth out chipped cooling fins, check motor mounts, install a bearing seal kit, remove un-used wiring (ie; lights), clean the motor component, wipe a very small amount of dielectric grease around the plug ribs, and install blank silicone plugs into the connector (s).

…preventative maintenance stuff.


Found a frame/ motor mount crack on a friend’s bike.

Edit; Pete pointed out the water ingress damage on that particular motor. That was donated to me for parts and the pcb was toast (and a few other things).

 

[Renton_Yorkshire]

Agree.

There obviously has to be a hole for the cranks to turn, so do NOT spray water in that area, pressurised or otherwise! Simply brush muck off with a dry brush.

Rocket science. Not.

I don't spray water anywhere. Never hosed any bike down to be fair - not even the shit ones I used to have to tolerate before I could afford anything decent

Muck-off spray, go and brew up then back to brush off the crud and wipe down with microfibre cloth

 

[Stihldog]

I tend to treat my EMTB’s like a cheap waterproof wrist watch. Sometimes a light watering is ok…and sometimes it’s not. I’ve rolled the dice .

A gentle shower spray is all I need after a dirty ride. However I have submerged the bike and myself several times with no effects. Recently had the motor rebuilt (5 years) with no signs of water ingress. It seems like each motor can be different. Perhaps it’s the assembly process, or maintenance, or riding style …or just plain luck .

 

[Just gan]

I don't spray water anywhere. Never hosed any bike down to be fair - not even the shit ones I used to have to tolerate before I could afford anything decent

Muck-off spray, go and brew up then back to brush off the crud and wipe down with microfibre cloth

It's a pity there isn't some cheap alternative these sprays are good but I doubt I would get 20 washes out of them , in winter anyway. Open to any suggestions bound to be something as good . Ten pound a gallon not a litre please

 

[Renton_Yorkshire]

It's a pity there isn't some cheap alternative these sprays are good but I doubt I would get 20 washes out of them , in winter anyway. Open to any suggestions bound to be something as good . Ten pound a gallon not a litre please

Agreed on that!!

Best way is to get the 25L can (currently £68 on Amazon), which works out like £2.75 a litre or something.

 

[Just gan]

Agreed on that!!

Best way is to get the 25L can (currently £68 on Amazon), which works out like £2.75 a litre or something.

I seen Gunk degreaser cheap as chips. I wondered about that . That's cheap though for mucoff about 5 gallon .

 

[RustyMTB]

If you can be bothered, data sheets on cleaning gear can be revealing. I keep a £10 5l bottle of Screwfix no nonsense degreaser after sussing out it's an identical formula to Halfords bike degreaser at £15 a litre.