1200 Changing Sprockets/chain And Servicing The Rear Axle

Hello everybody!

In the following thread I will give you a summary of my experience changing the chain and sprockets on my Multi, as well as what I found out about the rear axle, in case somebody wants to use my experience to do the same thing. I have a few short videos, however the battery on my camera died unexpectedly and I can't give you any video evidence of the work on the axle. I'll try to be descriptive.

So here it goes.

I got a DID XVM-Z 530 chain together with a Supersprox rear sprocket (42T) to test whether the change would benefit my riding habbits/style as I've read on countless comments on the matter. More on that later on. I also got a standard front sprocket (15T) together with a new washer. I started by removing the shift pedal to get some more space to work on there. The front sprocket cover is a bitch to get off, so removing the pedal was a good move. It didn't take long to get to the front sprocket. You can watch in the video here. For all you greeks out there, excuse the language I use when I discover that the locking nut is not tightened . YES! I unscrewed the locking nut with my hand! The only thing that was keeping the nut from unscrewing was the bent washer! (good thing). Oh! and the rust on the axle :smile:.
I bought the bike second hand (25K kms on the clock) but to the best of my knowledge and the extensive service book of the bike, it never had a sprocket change (which is quite normal for that mileage). So, unless I am missing something important here, I can only assume that the bike came like that from the factory. Needless to say, I am not happy at all. If anybody of you has any information that sprockets and chains are assembled by the dealer (or any other info that may explain this) please let me know. I would be really happy about your comments.
Moving to the rear axle, things are a bit different. I couldn't unscrew the nuts by hand this time (also a good thing). I used a 3/4" air wrench to undo the rear wheel nut (sprocket side). This is a powerful gun, used on truck wheels. It turned the sprocket side nut very easily as you can see here. This means that most probably the nut was tightened at the correct torque. But I guess I'll never know.
I have recently installed an oiler, which I have a hard time adjusting, as you can witness in the video. So I decided that I will remove the wheel, axle and eccentric hub as well to do a proper inspection and cleaning (which I am happy I did). So moving to the other side, things were again quite different. The bike had several rear wheel tyre changes. This meant that the tyre dealer never used a torque wrench (and therefore the correct torque setting) to tighten the wheel. This becomes very obvious in the following video where we try to get the nut out. It takes several attempts with the heavy gun. It's obvious that the wheel is tightened TOO much. I'm guessing nowhere near the suggested torque. But again, I'll never know. I just know that tightening with an air wrench is common practice (and never a good way to do it in my opinion). Off goes the RHS nut then and off goes the wheel.
Although the air wrench doesn't really need for the wheel to be blocked, the bike was in 1st gear all the time (which I took advantage of when I tightened the nuts). I moved on to cut the chain using Unior's chain cutting tool. Excellently machined but a little bit let down by poor depictions of how to use it. I am sure it will confuse a first timer. It had me pondering for a while and it's not the first time I've used one. After removing the chain, I went on to remove the sprocket. This proved quite difficult. I ended up using a bearing extractor, a heavy hammer and a lot of penetrating oil. As you can see in this video, there is substantial rust on the splined portion of the axle, where the sprocket carrier sits. It wasn't too bad but enough to warrant 10 minutes of hammering on the old sprocket with simultaneous use of the extractor to finally release it. You can also see the condition of the rear axle. Its obvious it has never been opened for a good clean. Separating the old sprocket from the carrier was very easy. I actually applied hand pressure and it came of right away. I cleaned the whole thing and inspected the rubber cush drives. They looked fine.
I moved on to removing the retaining bolts of the rear brake caliper and the rear ABS sensor in order to be able to get the axle out. This was by far the easiest part. I expected to be difficult since I've read a lot of horror stories about stuck axles and such but in my case it came out very easily just by tapping it with a soft mallet. I was surprised because there was charred grease on the right side of the axle where it sits on the wheel bearings and expect a more difficult extraction. I tested the bearings in the hub. I could easily turn them with my fingers and did not feel any drag, stepping or irregular movement. This is of course a personal view and I can't really relay the feeling but the bearings felt like being in a really good shape. I'm just writing this because I've read in numerous places that people couldn't move them with their hands, no matter how forcefully they tried. Maybe they should take a closer look and maybe replace them. Just a thought. I'm no certified mechanic
The next step was to remove the eccentric hub. I had a very difficult time when I was trying to adjust my chain lately (meaning the last 10000 kms ...), so I was pretty sure, there was too much dirt in there. In order to remove the hub, you need to remove the aluminum plaque that holds some washers, the rear caliper and the ABS sensor. This is retained by a huge c-clip on the rotor side. You need a good pair of reverse circlip pliers that can open beyond 4 cm, if you want to avoid damaging the aluminum arm. I didn't because I didn't have such a big tool but it's nothing to really worry about. But if you are very picky about keeping a part that will never see the light of day in pristine condition, get the appropriate tool first . I got the two retaining alen bolts out and I used a 3mm metal sheet to pry open the aluminum arm. I needed to stick something even wider in the gap, to keep it open while trying to get the hub out. It doesn't get off easily, so try to make your life as easy as it can be when doing this. It took quite a while of hammering with a mallet to get the hub out untouched.
I could finally see why I couldn't rotate the hub easily. Take a look at the first picture and you will see that you can probably plant flowers in the arm. And in the picture I have already cleaned it a bit. I removed a lot of grime/dust/sand from there. There is a little hole underneath for draining water but it's kind of a joke really. It's very small and it will get clogged in a matter of a few kilometers in the rain. So, my advice would be, to try and get the rear system cleaned and service at regular intervals. Together with the long service of the motor, every 24K kms, maybe. I know it's a lot of work and if you are forced to do it at a dealer you will have to pay for it but IMHO it's worth the trouble. I assume that if you do it at such intervals, it will be much easier to undo the components. I think it's even more worth it if you drive regularly in the rain (or if you dare getting it muddy off-road).
In the second picture, you can see the hub after I have cleaned it. It's actually silver :smiley:. You can see the dent I made when trying to adjust the chain, while the hub was stuck in the arm from the grit and grime. You can blame the crappy tool that comes in the kit as well. It's a piece of garbage. Buy a proper one or make your own if you can. You can thank Andy later for providing a drawing. As well as pictures for almost anything regarding the bike. Thanks again.
Having finished with all the cleaning, I started putting things back together, lubing everything that should be lubed. The biggest problem in assembling the whole thing back was getting the caliper carrier back on and putting the big c-clip in place. It was a pain. It involved some hammering but it wasn't damaged in the process. So it all went well. Now the chain adjustment is a piece of cake. Everything moves freely and smoothly.
I assembled the new chain again using the chain tool before tightening the front and rear sprocket nuts. You need the chain to stop the front sprocket from rotating when tightening it. I paid particular attention to pressing the chain at correct tolerances. You can use a vernier caliper to measure another link, then tighten with the tool until the safety pin link is exactly the same width. It's a bit fiddly but nothing to worry about.
To tighten the bolts back on, I used this torque wrench (30-350 Nm model). It is two feet long and I didn't need an extension bar or any other trickery to achieve the desired torque. However, it was a two men job. I was tightening and a friend was standing on the rear (non working) brake . It was enough for both front and rear nuts. By having the bike in 1st gear and nobody applying the brakes would just turn the engine. So have this in mind. Applied the correct torques everywhere and I was ready.

So, what's the final outcome? I very quiet bike first of all. The transmission is as good as in day one (which I never had the pleasure of enjoying, since I got the bike 2nd hand). It's really smooth, even the gears are engaged differently. I like it!
I also have a very smooth eccentric hub now. When the time comes to adjust the chain, I'm sure it will be easy. It was VERY educational. Now that I have seen the problems and tricks first hand, I believe I can do it again with minimal hassle and agony. Provided I have access to the proper tools of course. I also think that the extra two teeth will absolutely transform the bike. I didn't have the time to do a proper trip to test it (it's raining here) but in the few kms I did, there ware no hiccups in second gear and low rpm nor jaunting in first gear. So it looks very promising.

As I said before a big thanks goes to Andy for his resources which proved invaluable.
I also got some info from a post on another forum, which wasn't relative to the Multistrada but gave me a lot of info plus pictures. The similarities were evident. It was also a big help. Find it here.

So, thanks every body for the patience (if you reached this far) and let me know what you think on the front sprocket nut issue. I still can't believe it was loose ...

 

You can blame probably the last guy that changed your rear tire. They just tighten the nut with an air gun ... probably at about 500 Nm ...

 

Glad that it helped!
New chain still is 108 links. I have debated on this on other threads having to do with chain and sprocket change that the only thing that does is it shortens the wheelbase (and heightens the bike) but to no extend that I could tell. I could never put both feet solidly down on the ground anyway, so for me the change is non existent. Neither could I see any change in the bike's stability due the shortened wheelbase as it always has been exceptional.