Final drive concerns...

[sopwith camel]

Further to previous thread, have experienced vibrations at 70mph + through the bike over the course of a 3000 mile tour to Morocco and back. First thought was of FD bearing.

Given bike a check over on my return. Rear wheel does not spin freely out of gear as it used to - grinds to a halt straight away. Same situation if I put it into gear on it's stand and then pull the clutch in.

When the wheel is driving in gear, it sounds very rough... Holding the wheel, there is 1cm+ lateral play in the wheel.

Have checked wheel nuts which are all secure. Have also noted thread re: checking FD bearing (though can't find thread to show how to replace??!). I've not noticed any oil leaks however from the FD unit. Just wondering whether there is anything else I should be checking before I start to take it apart - or is it a trip to the local BMW dealer up the road with the deeds to my house in my pocket?

Bike is a 03 1150GSA running on Tourances... Mileage is approaching 28k.

Any advice greatly appreciated. Been reading quite a few threads on here, and some horror stories re: replacing FD unit etc.

Cheers

 

[Colban]

Further to previous thread, have experienced vibrations at 70mph + through the bike over the course of a 3000 mile tour to Morocco and back. First thought was of FD bearing.

Given bike a check over on my return. Rear wheel does not spin freely out of gear as it used to - grinds to a halt straight away. Same situation if I put it into gear on it's stand and then pull the clutch in.

When the wheel is driving in gear, it sounds very rough... Holding the wheel, there is 1cm+ lateral play in the wheel.

Have checked wheel nuts which are all secure. Have also noted thread re: checking FD bearing (though can't find thread to show how to replace??!). I've not noticed any oil leaks however from the FD unit. Just wondering whether there is anything else I should be checking before I start to take it apart - or is it a trip to the local BMW dealer up the road with the deeds to my house in my pocket?

Bike is a 03 1150GSA running on Tourances... Mileage is approaching 28k.

Any advice greatly appreciated. Been reading quite a few threads on here, and some horror stories re: replacing FD unit etc.

Cheers

Worn Tourances can give the vibrations you mention but the 10mm of play in the rear wheel suggests either the big bearing or your paralever bearing are shot/need adjusting.Have you drained the FD oil yet?.Do a seach for paralever bearing checks and heres a link to ADVrider tech stuff where you can find rearend stripdown info.
http://advwisdom.hogranch.com/Wisdom/

 

[motobiker]

Rear wheel does not spin freely out of gear as it used to...

A rear wheel that spins freely? now thats something I'ld like to see.

 

[elevensies]

having had FD bearing go twice, the common symptoms are

vibration through the pegs at most speeds
wollowing feel not as planted on the road
noise from rear of bike
oil leaking


dont run the bike on centre stand, it will fook up paralever bearing

the play in the wheel from rocking it will suggest the big bearing,

have you removed the wheel recently?

spinning rear wheel, no shouldnt be free as there is resistance through final drive and driveshaft,

 

[Pat]

Sounds like your paralever bearings are knackered.
If you put the bike on the centre stand and get somebody to rattle the wheel around at the 3 and 9 o'clock positions, can you see movement between the bevel box and the swing arm?
These bearings do go.....
I'm changing mine on Tuesday next..

 

[MattW]

dont run the bike on centre stand, it will fook up paralever bearing

How does that happen then?
(Not disagreeing, but it's the first I've heard of this and I'm struggling to picture how it could affect the paralever bearing...)

When the wheel is driving in gear, it sounds very rough... Holding the wheel, there is 1cm+ lateral play in the wheel.

As others have said, it sounds like the big FD big bearing - get someone to rock the wheel (12 and 6 o'clock then 3 and 9 o'clock)while you watch the FD to swingarm joint - it should be quite easy to see whether 1 cm of play is paralever bearings. Paralever bearings are fairly straightforward to replace (I've done several - loads on here about it). I've never changed a FD big bearing but others on here have - someone may have links to the relevant threads (failing that, I know there's stuff on Adventure Rider). It doesn't sound too difficult if you've got the tools and a bit of experience - I bought a spare bearing and seal a while ago and I'd have a go if mine went. Steptoe even posted how to do a roadside repair on ADV here: http://www.advrider.com/forums/showthread.php?t=87214&page=2&highlight=bearing

If you're not confident, a local independent will doubtless work out cheaper than a main dealer. However I did find that a main dealer was cheaper than motorworks etc for the bearing and seal.

 

[motobiker]

How does that happen then?
(Not disagreeing, but it's the first I've heard of this and I'm struggling to picture how it could affect the paralever bearing...)

your angle of dangle of the shaft is all wrong when up on a centre stand excessive freeplay at the gearbox end and the final drive having a crisis. The thing is designed to work under load... not hanging in the air supporting both it's weight and the weight of the rear wheel just try it and listen to the noises it makes.. its not a happy or pleasant one.

It's one of those things you should NEVER do.

 

[longdog]

your angle of dangle of the shaft is all wrong when up on a centre stand excessive freeplay at the gearbox end and the final drive having a crisis. The thing is designed to work under load... not hanging in the air supporting both it's weight and the weight of the rear wheel just try it and listen to the noises it makes.. its not a happy or pleasant one.

It's one of those things you should NEVER do.

Can't really see that, if it wasn't designed to work at those extreme angles of travel, then BMW wouldn't have allowed it to move to those extremes.

Are you saying that a bike, designed to cope with off-road use, will never have it's rear suspension unloaded with the engine running and driving the rear wheel?

Thought not

 

[motobiker]

You know matey... its clever answers like that, that make this forum such a great source of entertainment to me.

love it!!

 

[longdog]

Glad you appreciate a carefully considered, well thought out answer

 

[motobiker]

Glad you appreciate a carefully considered, well thought out answer

Oh,, I did. but for the precise opposite reason.... it was neither.


once again: NEVER allow the bike to run in gear while on the main-stand.

 

[MattW]

Oh,, I did. but for the precise opposite reason.... it was neither.


once again: NEVER allow the bike to run in gear while on the main-stand.

I'm fine with the concept of not running the centre stand. I guess I could forsee problems with drive shaft UJ angles or chatter doing bad things to the gear train.

However my original question was quite specific in response to elevensies and has been ignored by the last few posters - how does running the bike on its centre stand bu**er the paralever bearings?

 

[ciderman gs]

the paralever bearings would become damaged when the bike shot off the centre stand and through the garage door into the road run over by a bus oh and the engine would be fecked as well


oh yea have a look at steptoe sticky how to check your final drive

 

[elevensies]

your angle of dangle of the shaft is all wrong when up on a centre stand excessive freeplay at the gearbox end and the final drive having a crisis. The thing is designed to work under load... not hanging in the air supporting both it's weight and the weight of the rear wheel just try it and listen to the noises it makes.. its not a happy or pleasant one.

It's one of those things you should NEVER do.

what he says

 

[elevensies]

FFS this has been something thats been discussed so many times, and the general consensus from those who know say that due to the unsprung weight (fk all to do with design of travel) places unnecessary load on both the paralever bearing and the UJ.
Its exactly the same problem that can occur with r1100s owners who replace their torque arm with the GS one.

no need for smart comments, if its a positive contribution then all fair, if not why bother.

 

[MattW]

FFS this has been something thats been discussed so many times, and the general consensus from those who know say that due to the unsprung weight (fk all to do with design of travel) places unnecessary load on both the paralever bearing and the UJ.
Its exactly the same problem that can occur with r1100s owners who replace their torque arm with the GS one.

no need for smart comments, if its a positive contribution then all fair, if not why bother.

Unsprung weight? Where does that come into it?

If this is directed at me, then I did make a positive contribution (see post 6).

As an aside, I did also ask how running the bike on the centrestand could affect the paralever bearings and to be honest I'm still none the wiser. Perhaps we're talking about different paralever bearings - I'm talking about the two taper rollers which connect the FD to the swingarm

Anyway, life's too short for having arguments about heresay, I'll dip out of this.

 

[longdog]

FFS this has been something thats been discussed so many times, and the general consensus from those who know say that due to the unsprung weight (fk all to do with design of travel) places unnecessary load on both the paralever bearing and the UJ.
Its exactly the same problem that can occur with r1100s owners who replace their torque arm with the GS one.

no need for smart comments, if its a positive contribution then all fair, if not why bother.

No smart comments mate, just tell me why, because I can't see an engineering reason not to do it, unless of course, there is a basic design defect?

Unsprung weight is the weight consisting of the rear wheel, drive shaft, paralever arm, etc. basically the parts that move up and down and are controlled by the shock absorber. This is a constant, (subject to the weight of the tyre), whether the bike is on the centre stand or off it.

Now, are you telling me that this unsprung weight puts a strain on the bearings and shaft? Because what you have said doesn't make sense.

I can accept that there may be a strain at the extreme limits of travel, due to the angle that the UJ is subjected to, but the unsprung weight would not come into this. But a half decent designer would not allow his components to reach this limit under normal use. Now I repeat what I said earlier about reaching this angle under normal on and off-road use. The suspension would be fully extended, or close to it by riding over a hump-backed bridge for example, simulating the centre stand scenario. It would be engineering suicide for a design engineer to run a component so close to or beyond it's acceptable working limits.

I believe the GSA has a longer splined shaft with greater overlap to cope with it's longer suspension travel, but this longer travel is gained by the rear wheel moving through a greater arc, so the angle it moves through is greater than a standard GS. This suggests that a standard GS is working within its design limits. As a GSA often wears TKC tyres that are heavier than road based tyres, this suggests the unsprung weight angle, (if you'll pardon the pun), is invalid too.

Moving on, the scenario you depict with changing the torque arms between the R1100 and replacing it with a GS torgue arm actually changes the angle, not the unsprung weight.

Does this rate as a positive contribution to this thread?

 

[motobiker]

your mistake chap is trying to equate what happens to the back end of the bike while you're RIDING IT.

with....

What happens to it on the centre stand with the rear wheel in the air.

If you believe its no problem - test it. see how long you can stand there in front of your pride and joy listening to the ROW it makes while its doing something it was NEVER designed to do.

Running the engine in gear on the centre stand is a BAD IDEA.

In the owners manual BMW say.. switch off the engine before deploying the centre stand... they don't further qualify that. why should they?
There is absolutely no valid reason for EVER running the bike in gear on the centre stand. Why would you even want to?

beggars belief does this.

 

[chad]

Further to previous thread, have experienced vibrations at 70mph + through the bike over the course of a 3000 mile tour to Morocco and back. First thought was of FD bearing.

Given bike a check over on my return. Rear wheel does not spin freely out of gear as it used to - grinds to a halt straight away. Same situation if I put it into gear on it's stand and then pull the clutch in.

When the wheel is driving in gear, it sounds very rough... Holding the wheel, there is 1cm+ lateral play in the wheel.

Have checked wheel nuts which are all secure. Have also noted thread re: checking FD bearing (though can't find thread to show how to replace??!). I've not noticed any oil leaks however from the FD unit. Just wondering whether there is anything else I should be checking before I start to take it apart - or is it a trip to the local BMW dealer up the road with the deeds to my house in my pocket?

Bike is a 03 1150GSA running on Tourances... Mileage is approaching 28k.

Any advice greatly appreciated. Been reading quite a few threads on here, and some horror stories re: replacing FD unit etc.

Cheers

dont panic too much mate its a fairly simple job and the parts are not horrific either.

motorworks will supply what you need at a fair price,the first thing you need to do is pop off the wheel and remove the oil seal, that way you can get a good look at the bearing, but from your description it sounds fecked

the hardest part removing the bearing so try to lay your hands on a good puller gissa pm if your unsure of anything

 

[sopwith camel]

What have I started....??!

Only wanted to fix my bike...

Thanks for the tips at the start of the thread guys... got a weekend of further investigation coming up, then a potential trip to a mechanic if I lose my bottle with the spanners.

At least the impending bill might bring some smiles back to the thread...!