The Bosch Maintenance Thread

[Doomanic]

One for @EddieJJ this; a place to put maintenance tips for the Bosch DU.

 

[EddieJ]

Only joking. It seems like a very sensible thread starter.

I'll try and piece some details and photos together for it.

 

[Doomanic]

What size are the crank bolts?

I went to fit my FSA Self Extracting Crank Bolts today and I've bought the wrong size...

 

[EddieJ]

I just use one of these. Ice Toolz Crank Removal Tool with 8mm Hex Key

 

[Doomanic]

No problem.

If you look at the third photo down from the top, the sprocket has a guard, this has been removed from any of the other photos.

The guard if fitted, allows for a build up of mud, which can ultimately build up enough and make the chain slip. With one fitted there is also a greater chance of chain suck happening, again because of the build up of mud.

My crank puller arrived today so I thought I’d whip the chain guard off. Turns out the chain guard is also the drive sprocket lock nut...
luckily, I’d bought a lock nut from Ridewill just in case.

@EddieJJ, does that look right to you?

I also noticed that one of my covers has come unstuck. Not overly impressed with that, it’s only held on with double sided tape!

 

[EddieJ]

That looks like a fair bit of thread still left showing on the locking ring. Just popping out quickly to check mine, I have about 1mm of the locking ring thread showing. It could be just down to differing sprocket widths

It is hard to tell from the photo, but is there a second metal ring between the sprocket and the locking ring. If there is, and your bike is plus size, it should be on the inside of the sprocket, so that it maintains the chain line. Or at least that is how things are set up on my bike.

Ref the plastic cover, I'm afraid that is the norm.

 

[Doomanic]

That looks like a fair bit of thread still left showing on the locking ring.

Yes, there aren't many threads holding it on either. It's top hat shaped to clear the chain but it's not threaded down it's entire length. It doesn't fit the other way round.

is there a second metal ring between the sprocket and the locking ring. If there is, and your bike is plus size, it should be on the inside of the sprocket, so that it maintains the chain line.

Yes, there is.

Ref the plastic cover, I'm afraid that is the norm.

Poo. What's the best stuff to stick it back on with?

 

[EddieJ]

It was very long time ago that mine fell off. I have an idea that I might have used the thinnest smear possible of silicon.

My old cases used to have an additional and poorly designed cover around the sprocket. It was a constant battle to keep it in place, and in the end I just gave up and left it open. Not ideal, but I became fed up of rubbing on the chain.

I really love what KTM have done with the Fogo, and thee is no fuss or drama with ill fitting cases. The only stick on, is the CX badge on the motor casing. Hopefully it will stay there.

 

[Doomanic]

I opted to stay home today and do some maintenance, including checking the lube on the drive bearing. This is what I found;

Bugger all lube on there and surface rust. Not impressed. Again.
Now greasier than a bad mechanic’s overalls. Just hope I’m not too late.

 

[Eckythump]

I opted to stay home today and do some maintenance, including checking the lube on the drive bearing. This is what I found;
View attachment 375
Bugger all look be on there and surface rust. Not impressed. Again.
Now greasier than a bad mechanic’s overalls. Just hope I’m not too late.

Not sure if you have done it for greasing purposes but it looks like an o-ring is out of place in your photo. Between crank and drive hub.

 

[Doomanic]

FFS!

No, that wasn't me and I didn't notice. Looks like the crank is coming off again.

 

[Doomanic]

OK, crank pulled and whatever that was is gone...

 

[Eckythump]

OK, crank pulled and whatever that was is gone...

Odd coz there does look to be an o-ring half flipped out in the photo. Maybe an optical illusion....

 

[Doomanic]

I agree, but I've had a good look and it's not there now. It's possible that refitting the crank pushed it back into place.

 

[Eckythump]

I agree, but I've had a good look and it's not there now. It's possible that refitting the crank pushed it back into place.

Maybe so.

 

[EddieJ]

The little rubber O ring belongs here.



After you have installed the seal, the metal ring to compensate for plus size goes on next, then the sprocket, then the rubber O ring, and then finally the locking ring. Very odd how it has ended up where it has.

The lack of grease isn't a promising sign.

 

[Doomanic]

Yes, there is a thin o-ring that goes between the sprocket and the lock ring.

Incidentally, my drive sprocket is top-hat shaped and doesn't have the spacer ring.

 

[Doomanic]

The lack of grease isn't a promising sign.

I'm wondering if it's worth emailing Bosch?

 

[Yerbertie]

I opted to stay home today and do some maintenance, including checking the lube on the drive bearing. This is what I found;
View attachment 375
Bugger all lube on there and surface rust. Not impressed. Again.
Now greasier than a bad mechanic’s overalls. Just hope I’m not too late.

Doesn’t look like you have got the shaft seal

 

[Doomanic]

Shaft seal? Do you mean the plastic ring like this;

If so, it was removed so I could check the state of the bearing.

 

[Yerbertie]

Yes

Shaft seal? Do you mean the plastic ring like this;
View attachment 377
If so, it was removed so I could check the state of the bearing.

that’s the one

 

[eFat]

View attachment 377
There has been many bearing issues reported and this ring was added to the motors mid-2015. Bosch have a note about this: Upgrade protection ring

A belgium company sells a modified ring, MudStop, which should offer more protection. In any case I think it's very important to check regularly and add grease there.

 

[Marcus 8]

Hello, I would just like to add a comment on the subject of the VELOLAB protection ring for Bosch motor.
I use it from the beginning that I have my MOUSTACHE Race 8, first of all the ring can present a huge advantage compared to the risks of deterioration of the bearing.
Very easy to install in less than 15 minutes.
After about 800 Km of use I already removed twice this ring of protection to check if everything was OK. And, nothing to report, the ring does its job and no entry of moisture or dust is noteworthy.
So for the moment it works perfectly and it's doing the job.

I had an issue on my Haibike, the bearing was not in a good state after 2000 KM due to driving in mud condition. I suppose that when the sprocket turn, the chain bring mud which is pushed front of the bearing and after a certain time some humidity pass the join and go in. Bosch took it in guaranty and the motor was changed for free in less than a week. It was great but I prefere to avoid this kind of issue again...