Fixing Rear Wheel Alignment

[skx009]

I have a 2023 F 850 GS with 30,000 miles on it after two summers of lots of touring. Because this is basically my first bike, I haven't done any maintenance on it myself, relying on the 6,000 mile dealer services. However, I've been noticing a lot of chain slack recently (had the chain changed at 20,000 miles) and thought to myself, "Well, it can't be that hard to adjust it." So, I watched some videos and went to work.

Loosened the rear axle nut. Turned each of the adjustment bolts on left and right by a quarter. Tightened the nut again to 110nm. Voila! Less than 10 minutes.

But then I look at the adjustment markers on both sides and they're totally out of line. The left one maybe showed one bar, the right one three bars. So, since then I've spent probably an hour loosening and tightening the axle nut and trying to play around with the adjustment bolts, to no avail. I just can't get them to line up properly. (And by now I'm sure everything is out of spec.)

What do I do now? I live in an apartment and don't have a good spot to work on the bike, and also clearly don't know what I'm doing, so I'm tempted to just drop it off at the dealer come Tuesday, so that they can take the 30 minutes to make sure everything is in order. Can I tighten things up, even if the bars aren't well aligned, and ride the 4 miles to the garage?

 

[20774]

Welcome to the forum! Have you had a look at the DIY F-Twins Tech library?

F-Twins DIY/Tech Library

forums.bmwmoa.org

One of our members has created quite a few step-by-step posts for various tasks. Several involve the rear wheel. Look through them and see if you can pick up some pointers.

Good luck!

 

[omega man]

Well, first- Welcome to the forum!
Second, did you happen to note where the adjustments were before the quarter turn? There is a chance that it was off since the chain change?
I usually do a measurement of the axel (shaft) to the most convenient swingarm manufacturers hole.
I still “sight” the chain when I’m done……as a final confirmation.
Kurt’s recommendation to check the F-Twins DIY’s is a good one. The Dr has done some fine work.
BTW, all this is easier if your bike has a center stand or one of the stands the racers use. Anything to get the rear wheel up.
Let us know how you make out.
Good luck.
OM

 

[skx009]

Going through the DIY library right now! And no, I didn't check the alignments beforehand, unfortunately. My last service was done 5,000 miles ago, in early June, and I haven't touched the axle since then—and also haven't had any problems. My bike has a center stand, fortunately. This can't be that difficult, but I'm not sure what I'm doing wrong.

 

[omega man]

It isn’t really difficult. There may be some hints in the owners manual- if you have it.
OM

 

[kickstandsup]

This is a really handy little chain alignment tool. Often, the marks on the swing arm are a little off, this tool allows you to "sight" down the chain and get the sprockets aligned. That said, what you describe (one bar vs. three side to side) is a significant amount, more than usual manufacturing tolerance differences.

Motion Pro Chain Alignment Tool - RevZilla

The Motion Pro Chain Alignment Tool body clamps squarely to the rear sprocket so the alignment rod will indicate the sprocket alignment to the chain.

www.revzilla.com

One option, as you point out, is to go to the dealer and have them adjust it...maybe ask them to show you how. As has been suggested, it isn't that difficult, but it always helps to have someone show you. Countless videos on YouTube, fyi.

From a safety standpoint, you do want to be sure you're doing this right, i.e., right torque values, in the right order, the right slack. The actual alignment is the least of the issues; if out of alignment, the chain/sprockets will simply wear faster.

Good luck!

 

[skx009]

I did figure it out in the end—and yes, once you understand how the different parts work together, it's not that hard. I think my problem was that I loosened the rear axle nut too much initially, which then led the whole wheel to shift. And I guess once that's happened, you really have to get the whole setup properly aligned again to be able to use the adjustments again.

I've never felt the need to adjust the chain beforehand because it's always been more or less fine, and I try to follow the advice that a slightly loose chain is better than one that's too tight. But this time around, it was so loose that I could feel a bit of snatch during acceleration.

 

[omega man]

I did figure it out in the end—and yes, once you understand how the different parts work together, it's not that hard. I think my problem was that I loosened the rear axle nut too much initially, which then led the whole wheel to shift. And I guess once that's happened, you really have to get the whole setup properly aligned again to be able to use the adjustments again.

I've never felt the need to adjust the chain beforehand because it's always been more or less fine, and I try to follow the advice that a slightly loose chain is better than one that's too tight. But this time around, it was so loose that I could feel a bit of snatch during acceleration.

OM

 

[skx009]

This would have been easier and more interesting if I didn't have to do it in the 100 degree heat in a parking lot with people walking by and staring at me

 

[drneo66]

One trick that I like to employ, is to put the bike up on a center stand, axle bolt loose, set each adjustment bolt to where I want it (with the chain sag set), then use one of my wrenches (laid crosswise across the chain) and sandwich it between the chain and the rear sprocket as I roll the rear tire forward. This will take up the slack in the chain, and push the axle tight against the chain adjustment bolts. Then I can tighten the axel nut without having to fight the axle sliding out of whack.

Motion Pro makes a sprocket jammer tool that does the same thing, but you know what they say about BMW owners and being cheap...

 

[PGlaves]

One trick that I like to employ, is to put the bike up on a center stand, axle bolt loose, set each adjustment bolt to where I want it (with the chain sag set), then use one of my wrenches (laid crosswise across the chain) and sandwich it between the chain and the rear sprocket as I roll the rear tire forward. This will take up the slack in the chain, and push the axle tight against the chain adjustment bolts. Then I can tighten the axel nut without having to fight the axle sliding out of whack.

Motion Pro makes a sprocket jammer tool that does the same thing, but you know what they say about BMW owners and being cheap...

I do something similar. Once I have the adjusters set the way I want them I rotate the wheel backwards with the transmission in gear. This pulls the upper run of the chain taught, pulling the axle firmly against the adjusters as the axle nut is tightened.

 

[fbt80]

Wait...BMW's have chains too?