Drive train lash& swing arm adjustment

[chasgrips45]

A lot of stuff to cover! So I buy this nice 2000 R1100rs,with 6500 miles on the machine.It looks like a new bike. I drove it home from West Va to Franklin NC. I noticed what seemed to me like excessive drive line lash,or snatch.when I got home I pulled the tire & I put in in first & measured roughly 1 1/2 inches of wheel rotation at the brake disk. From "lock to lock" Now it could be that I`m ham handed after driving an Airhead for so long, but is that excessive? I`ve owned 3 other R1100rs & I didn`t feel such an on & off drive-line snatch. Am I crazy? Secondly ,while riding through the mountains today,I was startled to feel what I thought was a tire failure,or a wheel coming off. You know the feeling ,the bike just did not feel right. I stopped at the side of the road to take a look. Tire OK,wheel secure,I then gave the whole wheel a shake. I could hear & feel some lateral play at what seemed like the differential. First, maybe the driveline lash is" normal " & I just need to get used to smoother controls . But with the rear end play at the rear end,could it be that the swing arm,or differential pivots are loose? I just don`t like the way it handled. And its a bitch to drive smooth. Any ideas or suggestions? BTW ,the rear wheel rotates smoothly,with no leaks anywhere.

[Tony_K]

"Sounds like".... Impending final drive failure (or one of its variants). Hard to believe with less than 7k on the clock. I wouldn't ride it any further until you have done a full and complete inspection. Which means taking things apart, not just wiggling things. Sorry.

[chasgrips45]

How about the drive line lash?

[Tony_K]

I don't retain numbers like lash tolerances but if you have measured correctly it looks excessive. Other more number crunching minds will likely chime in. Irregardless that bike needs to come apart.

 

Upon rereading your first post, it would be "better" if the pivots were loose and they very well may be. Again, my come apart statement stands as rule.

[chasgrips45]

Maybe it`s because I`m running 31.5 psi in the tire!? I generally run 38, 40 psi in a Metzler rear no? I wouldn`t operate well either.

[Boffin]

How about the drive line lash?

 

About 2 inches of rotation is normal

 

Andy

[Clive Liddell]

Hi Andy,

That would be 2" at the tyre tread - he was measuring at the brake disk.

 

Also making a difference is the gear selected 1st is max play ad 5th should be a lot less

[AndyS]

"Sounds like".... Impending final drive failure (or one of its variants). Hard to believe with less than 7k on the clock. I wouldn't ride it any further until you have done a full and complete inspection. Which means taking things apart, not just wiggling things. Sorry.

 

Woh, not so quick.

The driveline lash needs to be rechecked and let us know for sure how much you have, what gear you are in, and where you are measuring it.

 

Before you commit to driveline failure, put the bike on the centrestand and get hold of the wheel from the side and try to twist it sideways. Do this at the 3 - 9 oclock position, then repeat at the 6 - 12 position. Any play? if so continue as per below.

Right, now get someone to push down real hard on the rear brake pedal and repeat the process again. Any play? If you still have play then it is most likely loose/worn FD PIVOT bearings. These can be retightened, but generally they need replacing. This is a whole lot easier and cheaper than an FD rebuild.

Let us know what you find, and someone will steer you with which repair route to follow.

 

All the best.

 

Andy

[ShovelStrokeEd]

I wouldn't think drive line failure is imminent or even likely.

 

Tire pressure should be up at around 38-40 PSI, pivots at both the swingarm and the final drive should be checked, as mentioned.

 

Take some things into account when trying to determine rotational "lash". The oilhead has a couple of extra gear pairs in there and a drive shaft with a rubber cush within. So the path from the engine to the rear wheel is bound to have some extra slop. Crown and pinion gear, then drive shaft with cush, then output shaft to intermediate shaft gear pairing, then intermediate gear to input shaft, there is also a spring cush on the input shaft, then input shaft to engine output shaft, then engine output shaft to crank. To add to this, there is a dog type shifting mechanism so no matter the gear there is the considerable play within the gears as the engagement dogs go from end to end of their travel.

 

Gears can't run at zero lash unless the are helical. Add a bit of play at the mating splines and you have your answer, keeping in mind that there are three sets of splines as well. I don't have the specification on this kind of test and think it would probably be better to compare your bike with a known good one of the same model.

 

If anything is going bad, I would suspect either the clutch splines or the cush drive in the driveshaft.

[chasgrips45]

I`ll go & make the check later in the day .According to the manual, the right side of the rear end pivot bearing should have over 100ft lbs of torque(Don`t remember exact number). The left side should have about 7. I guess what they want done is to load the bearing on one side. BTW the play I measured was at the brake disk. Yesterday ,when I checked for play at the rear end,tire installed (obviously), there was just a small? amount. I know it`s tough to be subjective when one says small amount.Does anyone have some type of spec that one should feel for? 1mm 2mm?

[AndyS]

I`ll go & make the check later in the day .According to the manual, the right side of the rear end pivot bearing should have over 100ft lbs of torque(Don`t remember exact number). The left side should have about 7. I guess what they want done is to load the bearing on one side. BTW the play I measured was at the brake disk. Yesterday ,when I checked for play at the rear end,tire installed (obviously), there was just a small? amount. I know it`s tough to be subjective when one says small amount.Does anyone have some type of spec that one should feel for? 1mm 2mm?

 

Right hand bearing stud bolt - clean thread and apply loctite 2701 then torque to 160Nm.

 

A lot of us have used a much lower locking medium such as loctite blue, and have found this to be more than adequate.

 

Once you have the loctite on, don't hang around very long with the assembly process of torquing the lefthand stud bolt and it's lock nut. The loctite starts to cure off amazingly quickly and will screw up your torque values - particularly on the 7Nm stud bolt.

 

Lefthand stud bolt (Make sure that the housing AND the bolt are meticulously clean and free from any old loctite. For the torque value to work, it needs to screw in VERY freely (the torque is just 7Nm).

 

The lock nut for this stud bolt is also tightened to 160Nm.

Make sure that the stud bolt does not rotate at all when tightening the lock nut.

 

 

As to how much play you can accept in the FD pivot, the answer is None! The bearings are taper units and by following the proceedure BMW give, this will result in no play.

 

If there is play, this will lead to horrible handling and much more accelerated wear in the pivot bearings.

 

Andy

 

 

 

[PapaJ]

Watch out for those torque values! I noticed in your post you said the left hand stud bolt should have 7 ft/lb. That is actually a newton meter value, torque value is something like .78 X the NM value which equate to just over 5 ft/lb. The right hand bolt at 160 NM equals something like 125 ft/lb. As Andy stated those value will only be good if you have absolutely no left over locktite in the threads. I use carb cleaner on the pins and threads to make sure they are clean, then a dental type pick to chase the threads in the swingarm.

As to the amount of play/lash in the driveline, it is not unusual to have 2" at the outside of the tire.

[chasgrips45]

So, I go to the tightness of the rear pivot bearings. Someone was in there before & must have really overtightened the bearings , I could see where on of the bushinbgs was funky klooking so I took the pivot pin out & sure enough it needed to be replaced .So I ordered 2 new ($34.00 a piece). I`ll torque it down properly . The only bitch in the works is inserting the new bearings. I get everything hot what needs to be hot ,everything cold that needs it. But I never make it downstairs in time !