• Welcome to the BMW Scooter Forums. Member registration disables ads and allows you to post and share. Register Here.

Driveline vibration elimination (hopefully!)

Nothing wrong with that (other than that it's on page 51-52, not 55-56).
I never heard of ASC calibration until now, I will execute that next time I take it out, but I would not expect ASC to have any relation to a driveline vibration.

In other news, I had the tire balanced today and that did make a noticeable difference. Testing it again 'dry', i.e. on the center stand, the vibration is much less. Not totally gone, but definitely much improved. Tomorrow I will take the rear wheel off again, to make sure the sheel-hub mating surfaces are absolutely clean. I am beginning to think that the shop I had fit my new tires last year did not do the best job. The other shop I went to today had to add quite a bit of weight to the wheel to balance the tire. Once I am happy with the mounting, will take it for another test run. But the 'dry run' today was certainly very encouraging.
 
So I think I am onto the cause: on the highway today I tested through to 100 mph and the vibration is definitely much less, although still present, but importantly it's now also clear that what is remaining is coming from the rear of the bike, not the middle (= engine) as I thought before. The reason it 'moved' was, I think, before I had the rear tire balanced, the vibration was so pronounced that the whole bike started to vibrate. Now that it's much less, only the rear is affected.

Which means two possible remaining causes IMO:
- the rear wheel bearings need replacing. There is indeed a tiny bit of play there in the wheel
- the actual tire itself has an irregular shape of sorts
- a combination of the two: as the tire is not perfect, any vibration is aggrevated by the small amount of play in the wheel bearings

All this makes sense to me, and also that it only starts at relatively high speeds, not at higher engine RPM.

For my next move, I will replace the wheel bearings and see what that does. If still not to my liking, I will get a new tire. The current one I only put on last year, but it's a Shinko el-cheapo, with which so far I have been satisfied (except that, in the wet, they slide quite easily) but if I need to put on a premium brand, I will happily do so if that eliminates the issue.

For now quite relieved that this is likely the cause, and not something deep within the engine block!

As it was time for a service, I changed the oil+filter, and also put in a new air filter (so, off came a lot of the tupperware on the right side. I had to remove the top side cover anyway to get at the OBD plug to reset the service warning with my Motoscan app). On my next longer run I will do the ASC recalibration.
 
Ceesie76 said:
So today I put in the next size chain rail and put in fresh gear oil. The old oil was quite dark. I also put in a fresh axle seal. The odd thing was, there was one bolt missing from the final drive case cover, and two had a small washer where the other ones did not. As if someone had been in there before me. Even though I bought the bike with only 1,960 miles on the clock, two years old and I never took it for any maintenance to BMW, have done all myself. I've only had some warranty and recall work done by BMW. So ... I put in the new no. 2 rail, assuming that the rail that was in there was the no. 1. But after I got it all buttoned back up, and took another look at the rail I had just taken out, I discovered that that was a number 2 also! Not the original no. 1. So clearly someone had been in there before me, and my best guess now is that it was the first owner who took it to BMW with some sort of complaint, and they swapped in the no 2 rail. So, I opened it all back up, put in the no. 3 that I had also bought (I bought the whole set, nos. 1, 2, 3 and 4) and the second time took me only about 20 minutes.
I then tested to see if upping the chain rail had made any difference. I discovered that, when you rev the engine with the bike on the centerstand, you can actually simulate it going all the way to max speed - the speedo registers the hypothetical speed at the RPMs you rev it at. And, at around 90 MPH, the vibration starts and gets progressively worse until the bike starts to actually move on its center stand due to the vibrations, at 105 or so it's no fun anymore. So, the chain rail nor the new belt or rollers/sliders have made any difference. So, I think Rolla Costa is right, it must be something more fundamental in the engine: balance shaft, vibration damper, a not-exactly-straight shaft, worn bearing - something. But, since it is fine all the way up to around 85, I think I will leave it be for now, just monitor to see it doesn't get worse and I am also looking forward to riding the F800ST that has more power and a higher top-end, hopefully without vibrations! It's also possible, perhaps, that the rear wheel is slightly out of round, or the tire is not balanced properly - I can have those things checked out still.
Click to expand...
The washers belong there in the rear casing.

As for the cap screw missing I found on a friend's bike, one was missing and the hole had no thread in it from the factory.
 
Thanks, well the washers were all missing except two random ones. No leaks though. I did replace the missing one in the center with a suitable bolt and there was thread for it in the casing.
 
Last edited:
Now that I’ve worn earplugs when riding, I think I felt that same vibration you are trying to get rid of. Normally it is drowned it the exhaust sounds, but my earmuffs kill the noise so I can feel vibrations more.
My theory is that could come from the fact that the final chain is constrained by plastic rails, not just up there in the air.
I guess we all have to get T-Maxes now, right? Their final belts are sublime, and maintenance-free. You get to re-tension them every rear tyre change.
If Buells had ABS I would have gotten a Buell…
 
Ceesie76 said:
So I think I am onto the cause: on the highway today I tested through to 100 mph and the vibration is definitely much less, although still present, but importantly it's now also clear that what is remaining is coming from the rear of the bike, not the middle (= engine) as I thought before. The reason it 'moved' was, I think, before I had the rear tire balanced, the vibration was so pronounced that the whole bike started to vibrate. Now that it's much less, only the rear is affected.

Which means two possible remaining causes IMO:
- the rear wheel bearings need replacing. There is indeed a tiny bit of play there in the wheel
- the actual tire itself has an irregular shape of sorts
- a combination of the two: as the tire is not perfect, any vibration is aggrevated by the small amount of play in the wheel bearings

All this makes sense to me, and also that it only starts at relatively high speeds, not at higher engine RPM.

For my next move, I will replace the wheel bearings and see what that does. If still not to my liking, I will get a new tire. The current one I only put on last year, but it's a Shinko el-cheapo, with which so far I have been satisfied (except that, in the wet, they slide quite easily) but if I need to put on a premium brand, I will happily do so if that eliminates the issue.

For now quite relieved that this is likely the cause, and not something deep within the engine block!

As it was time for a service, I changed the oil+filter, and also put in a new air filter (so, off came a lot of the tupperware on the right side. I had to remove the top side cover anyway to get at the OBD plug to reset the service warning with my Motoscan app). On my next longer run I will do the ASC recalibration.
Click to expand...
Thank you for the info i will get the rear tire replaced probably in about 1 month or
so at the dealer. I will tell the Mechanic about the vibration n the possible cause rear
wheel balancing n the wheel bearings need replacing. But first i will have him test ride
the bike about 90 or so. So he could feel it for himself.

You know i have the Shrinko tires as well. I have not had the slipping of the rear tire on
wet surfaces. Except the medal drain cover for the sewer under the ground. I have
slipped on the corner turn when wet. But other then that they are good.
 
Update is last Sunday I went to replace one of the rear wheel bearings (not the needle one that I had trouble finding, but the other one). After removing the rear final drive oil and cover, ran into the large 46 mm (or 45, different opinions out there) nut holding the rear axle and wheel hub all together. So I put it all back together and ordered a 46 mm 12 point socket that I am now waiting for to arrive. Replacing that bearing apparently involves heating it up / freezing the axle shaft it goes onto, as per the workshop manual. Hope I manage all that. Replacing that bearing is my last action on this issue, I think the tire place would have informed me if there would be any issue with the wheel or tire when they balanced it.
In other news, the F800ST is performing very well and it has absolutely no issue going to 100 mph and beyond if requested, no vibrations.
 
Last edited:
Yes I know that Greg. Although, not that different in the end. More protection from the elements, but not all that much more compared to the ST which is a Sport Touring bike with fairings, a small screen etc. But it's also a 2 cylinder motorcycle. What I found is more different is my single-cylinder supermoto Husaberg 550 FE - super nervous racehorse. I don't take that on the highways!
 
I had recently gone through all the same iterations as Ceesie76 is now. The 12-point socket is a 46mm to get the axle off. I used the old fashioned way of cutting an "X" on the inner race and break it with a chisel. Driving the inner race back on, I found a 1-1/2 inch pipe is perfect for seating the race and the outer sealed bearing. After all this, I had the tires rebalanced. When all is said and done, I still have some vibration, though diminished. There was an observation that it could be coming from the plastic chain guide. I could see how after going through the rear end and not solving the issue that the guide could be causing the vibration. As I mentioned before, mine seems to be rhythmic and seems to fade in and out and not so much a static vibration at a constant speed. I am not concerned anymore that it is a safety issue so much as a comfort issue. I may dig into it further, but for now I will just contend with it.
 
Pmccor said:
I had recently gone through all the same iterations as Ceesie76 is now. The 12-point socket is a 46mm to get the axle off. I used the old fashioned way of cutting an "X" on the inner race and break it with a chisel. Driving the inner race back on, I found a 1-1/2 inch pipe is perfect for seating the race and the outer sealed bearing. After all this, I had the tires rebalanced. When all is said and done, I still have some vibration, though diminished.
Click to expand...
Have you thought that you may have damaged the axel hamering it to break the inner race the hammering the inner race back on. It is fragile and thin walled.
You should have bought a bearing puller (I did, it was from princess auto $100) similar to Harbour freight.
Then To put it all back together using the 46mm nut, spacer, needle bearing and sprocket placing the (I forget the order) items in order

Sealed bearing first then the rest using the (old) big nut to press them back on as the nut pushes them on and creates space add more all go on easy and straight. At the end get a new nut as it has a lock tight on the thread. I have almost 100,000 on the bike and it is silky-smooth

the axel is really expensive
 
Last edited:
Have not yet taken the step to dismantle the rear axle again to try to replace the bearing. I dread the work a bit due to the press fit, need for blowtorch, freezing axle to fit new bearing etc, but at least the big socket did come in so I can tackle it when I get my courage up. Meanwhile I've been enjoying riding my 2007 F800ST for my weekly 2x125 mile commute, that thing goes over 100 mph effortlessly (and with 0 vibration) so able to avoid the big job so far. I will get to it in the next week or so, will report back.
 
Ceesie76 said:
Have not yet taken the step to dismantle the rear axle again to try to replace the bearing. I dread the work a bit due to the press fit, need for blowtorch, freezing axle to fit new bearing etc, but at least the big socket did come in so I can tackle it when I get my courage up. so able to avoid the big job so far. I will get to it in the next week or so, will report back.
Click to expand...
I didn't use heat or cooling it. Once I had the axle in my hand it took a half hour. Read my last post
 
Has there been any updates on the progress of this?

One thing to consider. Check the wear pattern on the rear tire by rubbing your hand over the tread in both the normal rotation and reverse rotation directions. If it has developed a 'snakes belly' pattern AGAINST the direction of rotation, this can cause a lot of resonance and vibration, especially at higher speeds. This is common in tires that only rotate in one direction all the time, and in motorcycles is caused by having too little rebound dampening. Unfortunately the BMW c650 and other scooters are not capable of rebound/compression damping adjustments, but when I did the top-end repair on my C-650 last month I also serviced the front shocks with heavier oil and an additional 25cc's per leg for more air-spring affect in compression. It steers and rides in a much more stable manner now. Going to do the same with the mono-shock soon. One improvement, though, was that the front end is much more planted and I have a less vibration at speed now, and under heavy braking it no longer bottoms the shocks if you hit a bump.

Having the rear tire out of balance is a definite bad thing. Glad you got that situated. Mine took 2.5 ounces in a single spot when I had it installed.


Good luck with the project. please keep us apprised
 
No update, because I solved the problem by buying a 2013 K1600GTL 'El Toro' that effortlessly and with 0 vibrations carries me like on a magic carpet the 122 miles to Los Angeles in the morning (and of course 122 miles back in the afternoon). So, have had less incentive to work on the C650, since I wanted to give the K1600 a full service and I had some 'honey do' list things to also take care of. Next is a fairly extensive service on our daily driver Mercedes GLK but shortly after that I should be able to make time to swap out one of the rear bearings that may be causing my little bit of play in the rear wheel. Also I was noticing my rear tire is getting to the end of its useful life and getting a quality new one might help as well. I will post updates once I have replaced the bearing and later the tire. It's bound to be one of these two things, having exhausted other usual suspects. I don't think the current tire is worn like you describe, but I will check in the daylight, tomorrow. Thanks for your suggestions.

20241113_095104.webp
 
You must log in or register to reply here.
Back
Top