"2nd dead bosch gen 4 motor not happy

AF1

Member
Jan 12, 2021
89
62
UK
Getting a little fed up with my bosch motor. 1st motor lasted just 1000miles, got replaced under warranty in covid, which took 3 months. The 2nd motor has never missed a beat until a week ago. Stopped at a mates and did 2 days of riding. Day one the sky opened up and it pissed it down big time, finished the ride, cleaned and oiled the bike and out for beer, 2nd days was cracking, 10 miles in code came up with an over load 500, ended the ride.
Got back home check the cable in the motor, one was loose, went out for a ride all good. today went out no codes 20 miles banked, put bike away, went to clean, oil check it, motor dead, nothing. Motor is out of warranty, so local shop to get it checked, but can see this as a new motor. The 2nd motor has only covered just over 1000miles. utterly fed up, these motors should last for 1000s of miles.
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Who thinks those affected by the poor design and longevity of the Gen4 should start a class action? Is there a Barrister on here affected by this?
 

RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
2,853
6,894
UK
Most barristers are rational & would tell you class actions are an American thing & here it's called group litigation. not much used outside of competition law breaches & life's too short.
 

Plummet

Flash Git
Mar 16, 2023
1,152
1,634
New Zealand
I feel sorry for all the worldly posters that are forced to ride in wet weather.
Well nobody is forced to ride in the wet. They choose to ride in the wet... as do I

Riding it the mud and grime and crap for half the year. I try no to go out it torrential rain, But muddy rides are par for the course in winter.

I'm at 2900km and still going strong. I have 2 mates who have had replacement motors under warrantee sub 5000km. Lets see how long mine lasts. It is what it is, If water gets in, so be it. I'm out there to ride. If i burn a motor out, i burn it out.

I'll do my best not to directly hose near the motor and often do wait till dry then brush down technique. But sometimes I have to get in there and clean shit. Particularly when the cooling vanes are jam packed with mud. That ain't good either. Two things will prematurely kill motors. Heat and moisture.
 

Tony4wd

Active member
Subscriber
Aug 3, 2022
260
225
Australia
As pointed out by 'Bearing Man', keep an eye on the 3 crankshaft greasing points to help keep water out. There are 2 main crankshaft seals with removeable covers held on by circlips. (video in the motor forum)
There's a third seal between the inner and outer crankshafts behind the right hand crank - this one is vulnerable but easy to access, just remove the crank and flick the plastic washer out, then clean and apply Bosch grease and press the plastic washer back in place. That third seal isn't designed to be greased but applying the tacky grease regularly in wet conditions should help keep the water out.
 

JP-NZ

E*POWAH Elite
Feb 17, 2022
1,201
916
Christchurch - New Zealand
Well nobody is forced to ride in the wet. They choose to ride in the wet... as do I
Think you missed the point many UK riders have to ride in the wet because they only get what seems like a few weeks of dry weather a year. At least thats what I keep reading on here..

I don't ride in the wet and still manage to get easily 10+ months of riding trails a year. Majority of our trails are closed in winter/wet anyway especially Christchurch adventure park. I guess its lucky Christchurch is so dry compared to the rest of NZ
 

Plummet

Flash Git
Mar 16, 2023
1,152
1,634
New Zealand
Think you missed the point many UK riders have to ride in the wet because they only get what seems like a few weeks of dry weather a year. At least thats what I keep reading on here..

I don't ride in the wet and still manage to get easily 10+ months of riding trails a year. Majority of our trails are closed in winter/wet anyway especially Christchurch adventure park. I guess its lucky Christchurch is so dry compared to the rest of NZ
I did get it. But still riding in the rain or mud/grime is still a choice. It's a choice I make too. If i didn't i'd lose about 60% of my ride time. This time of year its unusual to be dry. I think my last bone dry session was a month or so back.

Yeah, chch is dry, naki not so much.
 

RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
2,853
6,894
UK
Bearing man made the point in an EMBN video that mountain bikes make up about 10% of ebike sales. The vast majority of bikes are commuter, cargo types & never get anywhere near the beating MTB's receive & thus manufacturers are building motors to a specification that is entirely logical for the market demand. In other words, it's not their fault brands stick them in MTB's & sell them to nutters who go bombing round waterlogged hillsides in winter.

I.e. Were the figures reversed, they'd buld them stronger because they would have to do so.
 

AF1

Member
Jan 12, 2021
89
62
UK
My best tip would be to leave it alone! The Bosch Gen 4 is a very difficult motor to repair. Be very carful of the crankshaft, if you pull it or lift it before removing the torque sensor screw or armature and transfer gears, you will break the torque sensor. You will also struggle to remove and refit the main drive gear (a tool for refitting this gear is available from us or our partners if you are outside of the UK). DO NOT shock or drop the freewheel sleeve or crank assembly and definitely don't get a magnet near it. I could spend an hour telling you all the things to look out for, but if you decide to have a go, just be very carful and very delicate with it... Best of luck too.
1. "DO NOT shock or drop the freewheel sleeve or crank assembly" What happens if we get a crank strike, will that knock out sensors?
2. "and definitely don't get a magnet near it" does this permanently affect sensors or just throw an error? i.e, did these guys trash a motor by making this video: Error 510 motore bosch

3. I understand Bosch does not make sensors (or any other parts) available to anyone, are they made by Bosch or an outside manufacturer? The UK ‘right to repair’ legislation provides ‘professional repairers’ with access to spare parts and technical information from July 2021 - yet I understand you do not have access to these parts - is this true?
 
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RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
2,853
6,894
UK
Mate, you're coming on like a barrack room lawyer. You break your motor, warranty it or send it off to a repairer. Those are your options.
 

Ark

Active member
Mar 8, 2023
460
386
Newcastle Upon Tyne
Argue in a small claims court that it's not fit for purpose.
miles divided by days owned will be a pathetic number that proves that.

not even fit to last it's warranty when nipping to the shop every morning for a paper.

I'm at 1200miles on mine so far and no issues yet.
there's people in snow countries like norway, sweden, finland etc with 20,00km on their motors somehow.
It must be the splashing when a front wheel hits a large puddle thats getting them wet, if they last in the snow.

mudguards don't stop the impact splash

d. In other words, it's not their fault brands stick them in MTB's & sell them to nutters who go bombing round waterlogged hillsides in winter.
But then the motors have Mountain Bike modes etc so are clearly intended by the manufacturers to be used in mountain bikes.
 

AF1

Member
Jan 12, 2021
89
62
UK
Most barristers are rational & would tell you class actions are an American thing & here it's called group litigation. not much used outside of competition law breaches & life's too short.
Consumer Rights Act 2015 enabled the Competition Appeal Tribunal (“CAT”) to hear a broader range of private damages claims, having previously been restricted to hearing appeals of the UK’s Competition and Markets Authority (“CMA”).

Proceedings in the CAT have encompassed consumer related claims such as an ongoing claim against Sony which alleges that Sony abused their market dominant position and imposed unfair terms and conditions.

The option of representative actions Under CPR 19.8 (previously CPR 19.6) where claimants have the same interest in proceedings and can thereby be represented by a single representative to bring the claim on behalf of them all.
 
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AF1

Member
Jan 12, 2021
89
62
UK
You sound like fun.
So you think that Bosch are great and can do no wrong.

You think that motors failing in their thousands at low mileage is OK and those affected in their wallets should just swallow the rediculous costs involved, just because we cannot get a £5 sensor!

You think that junking otherwise servicable motors is ecologically sound.

You think that £1 per mile is an acceptable cost of owning an E-bike - more than most cars!

You don't think its worth persuing Bosch to facilitate a change in corporate thinking and design standards.

Are you sponsored by a Bike brand using Bosch motors?
 

RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
2,853
6,894
UK
You have a good day now friend. I'm off out for a ride on my 4000 miles in Bosch powered ebike. (y)
 

Gareth

Member
Apr 20, 2024
111
139
Ayrshire
You have a good day now friend. I'm off out for a ride on my 4000 miles in Bosch powered ebike.

I got 4300 miles out of mine and then it died. Water ingress killed the PCB.

Bosch won’t sell PCB’s, so the motor was a basket case. That is just crap.

Managed to get hold of a refurbished motor. That lasted 180 miles and then the clutch jammed. Water ingress again. Repaired free of charge as a good will gesture as motor repairs are not warranted for water ingress.

So I’m wondering how long my motor will last this time. Looking to see what I can do to keep the water out (no hose washing - servicing the seals on a regular basis etc).

But no these motors are not fit for purpose when used on a mountain bike.

As for choosing to ride in the rain. Well I live on the west coast of Scotland – it rains most days. During the summer we’ll usually get a few dry weeks – that’s it.

Yes I love my ebike – it is amazing. But it is ludicrously expensive to keep it running. Every bearing on the bike has been replaced. Full suspension overhaul front and rear. Just ordered a new front wheel as the hub has gone, new hub on the rear last year.

I am conflicted. I love it, but I am fed up shelling out for it. If I can’t find a way of getting more miles out of these motors, I may well just give up on ebikes.
 

Ark

Active member
Mar 8, 2023
460
386
Newcastle Upon Tyne
So I’m wondering how long my motor will last this time. Looking to see what I can do to keep the water out
You can refresh the grease under the motors seals.
Bosch sell a kit for it, there's a guide on how to do it on these forums somewhere, I think it might be a stickied post in the Bosch forum
 

RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
2,853
6,894
UK
There is a how to guide on here.. I filmed it.
 
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Bones

E*POWAH Elite
Subscriber
Apr 3, 2020
898
1,184
Harrogate
Mine has died at about 4.5k miles and just under 3 years old.
Error 500 basic code.
I've done the outer seal kit and bearings as per my video.
Been waiting for Bosch to tell me how much anal plundering it's going to cost for a new motor.😭
 
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Stihldog

Handheld Power Tool
Subscriber
Jun 10, 2020
3,573
5,045
Coquitlam, BC
Mine has died at about 4.5k miles and just under 3 years old.
Error 500 basic code.
I've done the outer seal kit and bearings as per my video.
Been waiting for Bosch to tell me how much anal plundering it's going to cost for a new motor.😭
A few years ago my neighbor purchased a new Bosch CX motor for about $800 Canadian Loonies. I think Pete ( @Bearing Man) can rebuild a motor for half that price.

He helped me out with a drive side casing once for the Bosch motor. It’s just unfortunate that he’s across the pond.
 

AF1

Member
Jan 12, 2021
89
62
UK
Mine has died at about 4.5k miles and just under 3 years old.
Error 500 basic code.
I've done the outer seal kit and bearings as per my video.
Been waiting for Bosch to tell me how much anal plundering it's going to cost for a new motor.😭
So probably the torque sensor. Sorry to hear that m8. www.e-motorrepairs.co.uk has some 2nd hand ones.

Looks like better news for me though, took my EMTB to the dealer who plugged it in, cleared down the faults and updated the firmware. I rode a couple of miles to test it and it seems good. Time will tell.

Had a big chat with the dealer and he said he found the correct Torque Sensors available from the factory in China which he did not persue. He also had 6 or so failed new & nearly new motors sat on the floor waiting to go back to Bosch under warranty.

Does anyone have the Part Number written on the Gen4 Torque Sensor they could give me?
 

Bones

E*POWAH Elite
Subscriber
Apr 3, 2020
898
1,184
Harrogate
Mine gave the error code after being stood for a week. I went to charge it up and it wasn't happy.
Can't remember what the rest of the code was but it wasn't moved when I started charging it, so not sure if the torque sensor is faulty as no load was applied.
I'm hoping Bosch might do a bit of discount 🤞
 

trigonul

New Member
Jan 30, 2024
2
2
Roman
Hi, the production cost of a Bosch CX Gen4 is max 350 £ So the retailer and Bosch are still making profit if they sell with 650 £ and they tell you it is a good offer 😅 That's why they have no interest to make a repairable motor 😮‍💨
 

AF1

Member
Jan 12, 2021
89
62
UK
Hi, the production cost of a Bosch CX Gen4 is max 350 £ So the retailer and Bosch are still making profit if they sell with 650 £ and they tell you it is a good offer 😅 That's why they have no interest to make a repairable motor 😮‍💨
Exactly!! How can we change Bosch's Ethos??? The motor is easily repairable if Bosch would release the necessary replacement spare parts !!!
 
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