Bosch Performance Line CX Gen 2 Strip Down

[Beancounter]

Next would be to fit the new bearings in the gear cluster which is this thing:

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But you'll remember that I got a little enthusiastic to try out the new press and I twatted it:

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Performance Line Bearings sell new holders/castings for £24 P+P and fitted my new bearings as part of the service so I kinda cheated on this bit. The key learning point is that you need to use something, possibly a 19mm socket, in place of the actual gears so that you can fit the bearings.

[Beancounter]

With the new bearings in the gear cluster and the LHS crank shaft bearing installed, next is to to fit the gear cluster and the crank into the motor. This is quite tricky because the two, independent parts have to be fitted at the same time and to do so requires a bit of careful jiggery so as to not damage the PCB.

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I was struggling to keep the main gear on the crank shaft as I tried to navigate the gear under the PCB and the crank into the bearing aperture, even resorting to using some paracord to help:

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No real success and I was getting very frustrated so headed off for a cuppa. As the kettle was boiling I remembered the bundle of circlips - yep, you've guessed it, the main gear should have been held in by a circlip on either side. In my relief at working out the problem I forgot to take a photo.

[Beancounter]

Once the crank is in the bearing it'll likely need a few taps with a soft-faced hammer to seat it fully home. Bear in mind where you're hitting with the hammer - if the are you hit deforms you won't be able to re-install the crank arms. Once the crank is seated remember to install a new circlip:

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Next is to re-install the torque sensor:

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[Beancounter]

Next up is to install the new transfer gear. Again, I cheated slightly on this because this came ready assembled in the kit so I didn't have to mess around with the cup bearing:

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[Beancounter]

Before installing the transfer gear you need to make sure the thin black wire/cable is correctly routed behind the white plastic clip and the white clip is not dislodged - it easily moves when you're lifting out the PCB and trying to remove the main motor gears.

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You can then install the transfer gear - this is my old one but you get the idea:

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Once in place it will help when re-fitting the RHS casing to the motor.

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[Beancounter]

Now on to the most annoying bit of the project - trying to re-fit the motor back into the frame. The weight and shape of the motor makes it difficult to place into the frame, you need to push down on the frame at the same time. Much easier to turn the bike upside down when the weight of the motor becomes an advantage. Must admit it took my missus suggesting it a few times before I gave in a tried it.

Finally on to the test ride this morning. Only went around the block but the motor is silent and the crank spins freely with no lateral play in it. Very happy.

Now I've done it once I'd do it again. Performance Line Bearings sell all the bearings individually or you can buy more comprehensive Bosch kits. The kits also come with fitting instructions but they're very 'light touch'. If you're planning on doing it yourself and will be going into the motor and buying a kit, I'd suggest buying the kit first so that you can see what bits come pre-assembled as it will save time and effort with some dismantling.

Big shout out to Performance Line Bearings/Ebike Motor Centre too, their videos are very helpful though it's still advisable to take lots of photos and notes as you go.

A quick tally of costs:

£100 - hydraulic bench press
£30 - bearing puller
£25 - bearing press
£190 - Bosch Service Kit +

I reckon to pay EMC to do it would have been about £350 but would obviously have been a lot quicker and the work would be warrantied. YMMV.

[Nordboy]

Nice one, seems to have taken a load more patience than I would have had?

Hopefully it's as good as new and gives you miles more riding.

[weeksy]

Ace job mate.. hugely impressed and agree with Nord, you're a better man than I gunga din.

[Count Steer]

A quick tally of costs:

£100 - hydraulic bench press
£30 - bearing puller
£25 - bearing press
£190 - Bosch Service Kit +

I reckon to pay EMC to do it would have been about £350 but would obviously have been a lot quicker and the work would be warrantied. YMMV.

So you basically got a free bench press, bearing puller and bearing press.

Now you can start taking orders...and squeeze the assets.

[Beancounter]

Nice one, seems to have taken a load more patience than I would have had?

Hopefully it's as good as new and gives you miles more riding.

Ace job mate.. hugely impressed and agree with Nord, you're a better man than I gunga din.

I do tend to be quite cautious when working on anything mechanical especially if it's my first time doing something - the obvious exception being the gear cluster holder when I got overly excited about using the new press.

Trying to work out how long I spent on the job is difficult because it spanned a number of weekends but I reckon from getting the bike on to and off of the workshop stand was 20 hours. A lot of that was spent watching and re-watching How 2 videos, gingerly trying to prise open the motor was a good hour, setting up the press and being overly-cautious using it... Next time will be a lot quicker though I cold never be classed as a fast worker.

A quick tally of costs:

£100 - hydraulic bench press
£30 - bearing puller
£25 - bearing press
£190 - Bosch Service Kit +

I reckon to pay EMC to do it would have been about £350 but would obviously have been a lot quicker and the work would be warrantied. YMMV.

So you basically got a free bench press, bearing puller and bearing press.

Now you can start taking orders...and squeeze the assets.

Only if peeps weren't in a hurry and not wanting a receipt.

[Beancounter]

Went to Cwmcarn on Saturday, was a good testing ground for the motor rebuild - all went well, no issues at all with the motor.

Also went to BPW with an uplift newbie, his bike didn't fare so well. Rear mech stop working so his chain kept falling off because his mech wouldn't tension the chain. He managed to fix this eventually, was making some nasty graunching noises though. His rear brake also failed, you'd pull the lever and could hear what sounded like air escaping from the caliper. I'm guessing very worn pads and overly extended pistons. I'd forgotten that his approach to maintenance was to run the other way.

[weeksy]

Went to Cwmcarn on Saturday, was a good testing ground for the motor rebuild - all went well, no issues at all with the motor.

Also went to BPW with an uplift newbie, his bike didn't fare so well. Rear mech stop working so his chain kept falling off because his mech wouldn't tension the chain. He managed to fix this eventually, was making some nasty graunching noises though. His rear brake also failed, you'd pull the lever and could hear what sounded like air escaping from the caliper. I'm guessing very worn pads and overly extended pistons. I'd forgotten that his approach to maintenance was to run the other way.

31st Oct Dyfi, 1st Nov Dyfi, 16th Nov BPW

[Beancounter]

Went to Cwmcarn on Saturday, was a good testing ground for the motor rebuild - all went well, no issues at all with the motor.

Also went to BPW with an uplift newbie, his bike didn't fare so well. Rear mech stop working so his chain kept falling off because his mech wouldn't tension the chain. He managed to fix this eventually, was making some nasty graunching noises though. His rear brake also failed, you'd pull the lever and could hear what sounded like air escaping from the caliper. I'm guessing very worn pads and overly extended pistons. I'd forgotten that his approach to maintenance was to run the other way.

31st Oct Dyfi, 1st Nov Dyfi, 16th Nov BPW

BPW on 16th is a possibility.

[weeksy]

Went to Cwmcarn on Saturday, was a good testing ground for the motor rebuild - all went well, no issues at all with the motor.

Also went to BPW with an uplift newbie, his bike didn't fare so well. Rear mech stop working so his chain kept falling off because his mech wouldn't tension the chain. He managed to fix this eventually, was making some nasty graunching noises though. His rear brake also failed, you'd pull the lever and could hear what sounded like air escaping from the caliper. I'm guessing very worn pads and overly extended pistons. I'd forgotten that his approach to maintenance was to run the other way.

31st Oct Dyfi, 1st Nov Dyfi, 16th Nov BPW

BPW on 16th is a possibility.

I'm gonna book later but a few of the locals are in.... no kids on this one, grown ups only. (in a loose sense of the term)

[Nessim]

Hi everyone,
I'm a bicycle mechanic and I'm stuck on a Bosch Performance Line Speed Gen2 fitted to a 2019 Centurion Lhasa.
The bike is completely original and has never been opened or modified.
I'm replacing the drivetrain because a new 11-speed chain skips on the front 17T sprocket under load. The rear cassette and derailleur work perfectly, so the problem is clearly at the motor sprocket.
Here's the issue:
Left crank removed.
Right crank removed.
No visible Bosch lockring.
The two small holes behind the splines rotate freely (they appear to be part of the freewheel, not a lockring).
The sprocket has absolutely no axial play.
It won't pull off the shaft.
Has anyone dismantled this exact FSA/Bosch Gen2 setup?
Is there a hidden retaining ring, a pressed-on carrier, or does the motor have to be opened from the inside?
Photos attached.
Thanks in advance.

[Taff]

The sprocket lock ring is fitted on the outside if that ring, it had castlations on the outside and needs a special tool to undo it, which is only a couple of pounds on eBay.
Im pretty sure it has a left hand thread , and you'll need the non drive side crank arm fitted to contract you when you're undoing it.

Loads of videos on YouTube.