"2nd dead bosch gen 4 motor not happy

irie

E*POWAH Elite World Champion
Subscriber
May 2, 2022
2,751
2,826
Chichester, W.Sussex, UK
Just in case you didn't realise, I am Peter, owner of the eBike Motor Centre 🙂. Sorry, we didn't realise you were an EMTB Forum member when you called. We do have a few parts put by for special people ;)
Thanks Peter! Talked with you on 5th May then called back on 7th June and talked with David. And yes, I am "special" because my wife says so and she's always right. Sometimes! 😉 Will call you then bring the two 2022 Rail 5's sometime after 15th July when it's convenient for you. (y)
 
Last edited:

AF1

Member
Jan 12, 2021
89
62
UK
Don't lose faith just yet, they're not all this bad! There are thousands of people out there riding around on high mileage motors and no problems at all 👍
Hi Pete, can you outline what parts you are using for the upgrade? Have you found a way to fit 2 seals for 1 or is it just better seals? Are you using corrosion proof bearings SS/ceramic? What is the current situation with faulty circuit boards?
 

Bearing Man

Ebike Motor Centre
Patreon
Sep 29, 2018
977
2,336
UK
Hi Pete, can you outline what parts you are using for the upgrade? Have you found a way to fit 2 seals for 1 or is it just better seals? Are you using corrosion proof bearings SS/ceramic? What is the current situation with faulty circuit boards?
As stated above, all will be revealed soon. I can tell you that the reason for failure on this motor is quite interesting. I will do a full post as soon as we are ready with our stock, part numbering, pricing etc.
 

RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
2,875
6,969
UK
Mine's on its way. Look after it Pete, I'm missing it already, we've been through so much together. 😢

rBb70r2j.jpg
 

Bearing Man

Ebike Motor Centre
Patreon
Sep 29, 2018
977
2,336
UK
Mine should be arriving at yours tomorrow. As I'm out of action for a month with a broken hand, is it worth waiting for better parts?
I think you sent your motor to us in the nick of time Bones! I hope you don't mind us sharing our findings on the forum, but I think those on this thread will find it interesting.
You reported your motor had a slight whine, but apart from that, felt good. This is a very typical and common statement by many people who send their motors to us, but hopefully the photos we took of your motor will show the importance of being very in tune with your motor and knowing what to look and listen for.

The picture below shows inside the drive side motor cover, the right hand crankshaft bearing and smaller transfer gear support bearing. The right hand crankshaft bearing is seized solid (this often happens when working motors are sent in with residual water left in the bearings). The light grey discolouration of the grease around the outside of the dark grease is caused by water emulsifying with the grease. The dark colouration is some sort of contamination, almost like a Moly grease? Or chain lube? The dryer consistency of this grease in the centre, by the bearing is caused by dirt contamination from within the bearing itself.
20240619_111213.jpg


The picture below shows what's left of seal inside of the freewheel sleeve that fits through the right hand crankshaft bearing and supports the chainring spider. (No, it should not have all that dirt in it). The plastic bush below the seal was quite badly worn.
20240619_112405.jpg


You can see the rust damage on the bearing surface of the crankshaft below. The crankshaft fits through the freewheel sleeve above and the damage to the crankshaft is why the plastic bushes don't last 5 minutes! It also gives you a clue as to how the water gets into a Gen 4.
20240619_112346.jpg


Looking at the other end of the crankshaft below, it shows where the cadence cage (or black plastic bit) sits against the left hand crankshaft bearing. The rusty looking grease is from the left hand crankshaft bearing.
20240619_112021.jpg


This is the left hand crankshaft bearing below and the main reason these fail, is because Bosch have fitted a metal shielded bearing. Meaning the bearing does not have a seal on the in side! Basically, the water runs down the crankshaft from the right hand freewheel sleeve seal and straight into the bearing.
20240619_112130.jpg


The transfer gear cluster and armature below should look clean, and the grease should be a nice light tan colour. Unfortunately this is far from that and all the bearings where rough and worn. This is where the whining noise was coming from.
20240619_111652.jpg


The drive gear below had transferred the debris and dirt from the right hand crank bearing and cover to the transfer gear cluster.
20240619_111310.jpg


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.
20240619_103246.jpg
20240619_103252.jpg

When 'Bones' motor arrived, it had several unusual fault codes which are usually a sign of a wet motor. The codes are caused when beads of water or droplets of dirt get onto the PCB, bridge out between components, then dry out and often the code will disappear. If this water bridges something important, that's usually the end of your motor. Bones has been a very lucky boy!
Please note: This motor had definitely not been pressure washed or showed signs of any abuse what so ever. It just shows that there is a very serous issue here. We tried to warn Bosch this was coming but after a reasonable meeting we were subsequently ignored. This is why we have put the effort into getting a solution made.
 

Bones

E*POWAH Elite
Subscriber
Apr 3, 2020
913
1,228
Harrogate
I think you sent your motor to us in the nick of time Bones! I hope you don't mind us sharing our findings on the forum, but I think those on this thread will find it interesting.
You reported your motor had a slight whine, but apart from that, felt good. This is a very typical and common statement by many people who send their motors to us, but hopefully the photos we took of your motor will show the importance of being very in tune with your motor and knowing what to look and listen for.

The picture below shows inside the drive side motor cover, the right hand crankshaft bearing and smaller transfer gear support bearing. The right hand crankshaft bearing is seized solid (this often happens when working motors are sent in with residual water left in the bearings). The light grey discolouration of the grease around the outside of the dark grease is caused by water emulsifying with the grease. The dark colouration is some sort of contamination, almost like a Moly grease? Or chain lube? The dryer consistency of this grease in the centre, by the bearing is caused by dirt contamination from within the bearing itself.
View attachment 142478

The picture below shows what's left of seal inside of the freewheel sleeve that fits through the right hand crankshaft bearing and supports the chainring spider. (No, it should not have all that dirt in it). The plastic bush below the seal was quite badly worn.
View attachment 142479

You can see the rust damage on the bearing surface of the crankshaft below. The crankshaft fits through the freewheel sleeve above and the damage to the crankshaft is why the plastic bushes don't last 5 minutes! It also gives you a clue as to how the water gets into a Gen 4.
View attachment 142480

Looking at the other end of the crankshaft below, it shows where the cadence cage (or black plastic bit) sits against the left hand crankshaft bearing. The rusty looking grease is from the left hand crankshaft bearing.
View attachment 142481

This is the left hand crankshaft bearing below and the main reason these fail, is because Bosch have fitted a metal shielded bearing. Meaning the bearing does not have a seal on the in side! Basically, the water runs down the crankshaft from the right hand freewheel sleeve seal and straight into the bearing.
View attachment 142482

The transfer gear cluster and armature below should look clean, and the grease should be a nice light tan colour. Unfortunately this is far from that and all the bearings where rough and worn. This is where the whining noise was coming from.
View attachment 142483

The drive gear below had transferred the debris and dirt from the right hand crank bearing and cover to the transfer gear cluster.
View attachment 142484

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.
View attachment 142485 View attachment 142486
When 'Bones' motor arrived, it had several unusual fault codes which are usually a sign of a wet motor. The codes are caused when beads of water or droplets of dirt get onto the PCB, bridge out between components, then dry out and often the code will disappear. If this water bridges something important, that's usually the end of your motor. Bones has been a very lucky boy!
Please note: This motor had definitely not been pressure washed or showed signs of any abuse what so ever. It just shows that there is a very serous issue here. We tried to warn Bosch this was coming but after a reasonable meeting we were subsequently ignored. This is why we have put the effort into getting a solution made.
Wow that looks a mess Peter!.
Seems like I wasted my time with the seal kit a few months back 🤔
Great pictures and diagnosis.
Do I need to sell the family jewellery?
Like you say it's never been pressure washed but it's been through plenty of water crossings.
It is an MTB that gets some stick and we are in the UK 😀
 

Bearing Man

Ebike Motor Centre
Patreon
Sep 29, 2018
977
2,336
UK
Wow that looks a mess Peter!.
Seems like I wasted my time with the seal kit a few months back 🤔
Great pictures and diagnosis.
Do I need to sell the family jewellery?
Like you say it's never been pressure washed but it's been through plenty of water crossings.
It is an MTB that gets some stick and we are in the UK 😀
Have PM'd you @Bones 👍
 

rutger

Member
Sep 27, 2021
9
9
NL
I think you sent your motor to us in the nick of time Bones! I hope you don't mind us sharing our findings on the forum, but I think those on this thread will find it interesting.
You reported your motor had a slight whine, but apart from that, felt good. This is a very typical and common statement by many people who send their motors to us, but hopefully the photos we took of your motor will show the importance of being very in tune with your motor and knowing what to look and listen for.

The picture below shows inside the drive side motor cover, the right hand crankshaft bearing and smaller transfer gear support bearing. The right hand crankshaft bearing is seized solid (this often happens when working motors are sent in with residual water left in the bearings). The light grey discolouration of the grease around the outside of the dark grease is caused by water emulsifying with the grease. The dark colouration is some sort of contamination, almost like a Moly grease? Or chain lube? The dryer consistency of this grease in the centre, by the bearing is caused by dirt contamination from within the bearing itself.
View attachment 142478

The picture below shows what's left of seal inside of the freewheel sleeve that fits through the right hand crankshaft bearing and supports the chainring spider. (No, it should not have all that dirt in it). The plastic bush below the seal was quite badly worn.
View attachment 142479

You can see the rust damage on the bearing surface of the crankshaft below. The crankshaft fits through the freewheel sleeve above and the damage to the crankshaft is why the plastic bushes don't last 5 minutes! It also gives you a clue as to how the water gets into a Gen 4.
View attachment 142480

Looking at the other end of the crankshaft below, it shows where the cadence cage (or black plastic bit) sits against the left hand crankshaft bearing. The rusty looking grease is from the left hand crankshaft bearing.
View attachment 142481

This is the left hand crankshaft bearing below and the main reason these fail, is because Bosch have fitted a metal shielded bearing. Meaning the bearing does not have a seal on the in side! Basically, the water runs down the crankshaft from the right hand freewheel sleeve seal and straight into the bearing.
View attachment 142482

The transfer gear cluster and armature below should look clean, and the grease should be a nice light tan colour. Unfortunately this is far from that and all the bearings where rough and worn. This is where the whining noise was coming from.
View attachment 142483

The drive gear below had transferred the debris and dirt from the right hand crank bearing and cover to the transfer gear cluster.
View attachment 142484

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.
View attachment 142485 View attachment 142486
When 'Bones' motor arrived, it had several unusual fault codes which are usually a sign of a wet motor. The codes are caused when beads of water or droplets of dirt get onto the PCB, bridge out between components, then dry out and often the code will disappear. If this water bridges something important, that's usually the end of your motor. Bones has been a very lucky boy!
Please note: This motor had definitely not been pressure washed or showed signs of any abuse what so ever. It just shows that there is a very serous issue here. We tried to warn Bosch this was coming but after a reasonable meeting we were subsequently ignored. This is why we have put the effort into getting a solution made.
THANK YOU FOR POSTING THE PHOTOS.... NOW I CAN BE ALMOST CERTAIN THAT MY ENGINE HAS ALSO BEEN BREAK DOWN THIS WAY
IN MY PHOTO YOU CAN SEE A BROWN EDGE AROUND THE BEARING (LEFT SIDE BEARING) THIS BROWN EDGE WAS THERE FOR A FEW HUNDRED KM UNTIL IT WON'T START (WITHOUT AN ERROR CODE...) IN YOUR PHOTO IT APPEARS THAT
IT APPEARS THAT THE PAINT LAYER IS COMING LOOSE THROUGH THE WATER
WHICH MAY CAUSE CLOSURE


SORRY FOR THE BAD TRANSLATION VANUIT HET NEDRLANDS

Schermafbeelding 2024-06-16 115928.png
 

Plummet

Flash Git
Mar 16, 2023
1,152
1,635
New Zealand
My motor died last week. 11 months, 3000km. I've ridden some pretty harsh conditions. So assuming water ingress.

Let's see what happens

In the mean time I'm back on the mtb, which doesn't bother me as I'm mtbing 50% of the time anyway.
 

Plummet

Flash Git
Mar 16, 2023
1,152
1,635
New Zealand
N
Was the motor noisy/whining before it died?

My bosch CX is has developed a noticeable whine recently - started carrying a tow rope so the dog can get me home :)
Not overly, just started cutting out and getting all jittery before it cut out to a point where I called it and took it into the shop. Still waiting on the diagnostic from the bike shop.
 

Bearing Man

Ebike Motor Centre
Patreon
Sep 29, 2018
977
2,336
UK
THANK YOU FOR POSTING THE PHOTOS.... NOW I CAN BE ALMOST CERTAIN THAT MY ENGINE HAS ALSO BEEN BREAK DOWN THIS WAY
IN MY PHOTO YOU CAN SEE A BROWN EDGE AROUND THE BEARING (LEFT SIDE BEARING) THIS BROWN EDGE WAS THERE FOR A FEW HUNDRED KM UNTIL IT WON'T START (WITHOUT AN ERROR CODE...) IN YOUR PHOTO IT APPEARS THAT
IT APPEARS THAT THE PAINT LAYER IS COMING LOOSE THROUGH THE WATER
WHICH MAY CAUSE CLOSURE


SORRY FOR THE BAD TRANSLATION VANUIT HET NEDRLANDS

View attachment 142645
This is normally caused by rust (corrosion) coming out of the bearing.
 

Bndit

Active member
Jul 14, 2022
334
394
Finland
Just got email from LBS that I`ll get new motor with 50% discount, so it`s about 500€ with labour. I`m happy with it. It`s my commuter, Focus Aventura 11k km on the clock. 4000km and one year first CX4 died and now after two years and 7000km after that, the second motor dies. So the motors lasted together little over three years. No mechanical failure, electronics. Now I get new motor with 2 years warranty 👍First time when it was replaced under warranty, it took five weeks, this time about two months 😂. Specialized was replaced in 1 1/2 weeks, free of charge even it was out of warranty 😀
 

JP-NZ

E*POWAH Elite
Feb 17, 2022
1,211
932
Christchurch - New Zealand
Not overly, just started cutting out and getting all jittery before it cut out to a point where I called it and took it into the shop. Still waiting on the diagnostic from the bike shop.
Do you deal with Bosch in NZ for warranty now, Being mail order from Pole I don't suppose you have much luck with them for warranty?
 

Plummet

Flash Git
Mar 16, 2023
1,152
1,635
New Zealand
Do you deal with Bosch in NZ for warranty now, Being mail order from Pole I don't suppose you have much luck with them for warranty?
Yep, Its currently at the bike shop and they are dealing direct with bosch nz.
PS that is how it would role if pole was still in business and with any other brand. The bike shop deals directly with bosch.

With that said i'm likely to be charges labour for work done by the bike shop. I'm ok with that, they need to make money and I enjoyed the cost savings of importing a bicycle far cheaper than what I could purchase a similar thing here in NZ.
 

JP-NZ

E*POWAH Elite
Feb 17, 2022
1,211
932
Christchurch - New Zealand
Yep, Its currently at the bike shop and they are dealing direct with bosch nz.
PS that is how it would role if pole was still in business and with any other brand. The bike shop deals directly with bosch.

With that said i'm likely to be charges labour for work done by the bike shop. I'm ok with that, they need to make money and I enjoyed the cost savings of importing a bicycle far cheaper than what I could purchase a similar thing here in NZ.
Nice, a guy I know works at Marleen here in Christchurch that deal with most Bosch stuff in NZ. Hope its nice quick swap for ya.
 

Bearing Man

Ebike Motor Centre
Patreon
Sep 29, 2018
977
2,336
UK
Wow that looks a mess Peter!.
Seems like I wasted my time with the seal kit a few months back 🤔
Great pictures and diagnosis.
Do I need to sell the family jewellery?
Like you say it's never been pressure washed but it's been through plenty of water crossings.
It is an MTB that gets some stick and we are in the UK 😀
This was a motor that just kept giving!! After overhauling your motor Bones, we popped it into our test bike and it still whined!:mad: This can only mean one thing, the top armature bearing had failed. This is extremely rare, but it's also the only, currently, unchangeable bearing in the whole motor. This goes on... we can't change the armature bearing because the magnet that tells the sensor on the PCB when to fire each phase of the three phase motor, is pressed on above this bearing. The magnet is extremely difficult to remove and replace in exactly the right position, and best left well alone! This means that we can't just swap the armature either, because this is calibrated to the PCB.
So, you now have a quiet motor with a lower mileage, thanks to a donor motors PCB and armature.
For those of you with a "SMART" Bosch, this sort of repair will not be possible :cautious:
 

Bones

E*POWAH Elite
Subscriber
Apr 3, 2020
913
1,228
Harrogate
This was a motor that just kept giving!! After overhauling your motor Bones, we popped it into our test bike and it still whined!:mad: This can only mean one thing, the top armature bearing had failed. This is extremely rare, but it's also the only, currently, unchangeable bearing in the whole motor. This goes on... we can't change the armature bearing because the magnet that tells the sensor on the PCB when to fire each phase of the three phase motor, is pressed on above this bearing. The magnet is extremely difficult to remove and replace in exactly the right position, and best left well alone! This means that we can't just swap the armature either, because this is calibrated to the PCB.
So, you now have a quiet motor with a lower mileage, thanks to a donor motors PCB and armature.
For those of you with a "SMART" Bosch, this sort of repair will not be possible :cautious:
This is something that the home mechanic has no chance of successfully repairing if specialist like yourselfs won't takle it!
As per my PM, again many thanks for all the work involved and not giving in on the nightmare job!
Your a Star Peter, but keep that to yourself 🤔
 

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