Removing an 1150GS driveshaft

[R Savage]

I have encountered a brick wall in my search for a rumble free bike. SLM believe that my driveshaft needs to be replaced but my warrantors (Olympic) will not pay for it unless the shaft is actually flapping loose in the swinging arm. Therefore, I've got to remove it myself and take it to SLM for inspection.

From the .pdf manual, all appears straightforward: remove rear brake caliper, rear wheel, and shock absorber. Then heat, to loosen Loctite, and remove the two pairs of bolts that attach the final drive to the swinging arm and the swinging arm to the gearbox. This is where I get a little nervous; what do I heat the bolts with and how do I know that I have reached the required temperature?

Any other advice or guidance gratefully received.

Richard

 

[bandit]

Hot bolts

Rather than heating the bolts try :


A sharp tap with a hammer, try to tighten slightly then un do.

 

[R Savage]

Re: Hot bolts

Originally posted by bandit

Rather than heating the bolts try :


A sharp tap with a hammer, try to tighten slightly then un do.


Bandit, is this the voice of experience or optimism? The manual is explicit about heating Loctite 2701 to remove the bolts. This suggests to me that the bond is not broken that easily. I've looked at the Loctite site and now know an awful lot about staic strength and shear resistance but understand non of it!

Rgds Richard

 

[boxer]

Richard.

You may find

http://www.motobins.co.uk/cgi-bin/yabb/YaBB.cgi?board=general&action=display&num=949

useful especially the parts about heating the pivot bolts.

Regards.

Russ.

 

[Mick Fagan]

A friend removed his 1150GS swing arm a few weeks ago and he heated up the pivot bolts using my heat gun on it's lowest setting.

The heat gun has a 300W and a 500W setting and cost me $19.95 and is a real cheapie, but it does the job.

As far as heating is concerned you will notice a small odour as the lacquer starts to heat up. This seems to be about the right time to give the pivot bolts a nudge and it works. The same as on my 1100GS.

Officially BMW always seems to use 100C as the temperature on all other BMW bikes that I've worked on. Have a glass of water alongside and when it appears to be getting warm, sprinkle some water on and if it sizzles then it's at 100C, if it just runs off it isn't there yet!

Mick.

 

[R Savage]

Thanks for the direction to the Motobins pages - very helpful and comforting. Mick - no I'm not thanking my lucky stars that I have an 1150, especially as I'm seriosly considering fitting an 1100 final drive to try to get a sensible 1st gear!

Cheers Richard

 

[Mick Fagan]

Richard, a very good friend of mine has an 1150GS. He was frustrated at the gearing, compared to my 1100 that is.

Eventually he bought the diff for an 850GS brand new, and fitted it to his 1150. It bolts straight on, by the way.

The upshot is that after a very unscientific test of riding together, whereby I rode at a constant 3,000rpm indicated and he checked his at 2,900rpm and at 4,000rpm on my bike his was doing 3,900rpm.

This was pleasing to him as at last he had go in top gear when fully loaded and two up. Meaning he didn't have to drop down a gear when a hill the size of a speed hump appeared.

Another unscientific test was low speed travelling. We put our bikes in first with me leading and him following. We then let the bikes idle along in first. Slowly he caught up to me and passed. Before this change his bike in first gear would overtake mine, like a walker passing a stationery bike.

In short he now has the traction ability at slow speed that matches the 1100 gearing and speed. He is extremely happy. I think the Diff (reduction axle actually) cost him about $900.00 Australian Dollars.

You may wish to think this one over before doing anything drastic, eh?

Mick.

 

[Mick Fagan]

Richard, regarding driveshaft rumble, when you do pull your shaft out, check out the alignment of the universal joint yokes. I'm led to believe that they should align up.

If they are misaligned it would appear that the outer metal part has slipped in relation to the inner metal part. Both parts are joined together by rubber which provides a shock absorber situation.

Mick.

 

[R Savage]

Richard, a very good friend of mine has an 1150GS. He was frustrated at the gearing, compared to my 1100 that is.

Eventually he bought the diff for an 850GS brand new, and fitted it to his 1150. It bolts straight on, by the way.

I think the Diff (reduction axle actually) cost him about $900.00 Australian Dollars.

Mick.

Thanks Mick,

I was only thinking about the 1100GS final drive because I know of a chap in the US who has done the swop an is similarly pleased. A second hand 1100 final drive is about £280, while the one for an 850GS is £220

How carefully did your friend set the torque on the floating bearings?

Cheers Richard

 

[Mick Fagan]

Richard, both he and I are extremely careful about the torque settings of the bearing retaining bolts.

I purchased a new torque wrench when I bought my 1100 in 1998. That wrench goes from .5 to 20NM is calibrated and is very, very handy. Remember that the new 259 series of BMW bikes have quite a lot of low torque settings that are somewhere around the 4/6/8/10 & 16NMN mark so this torque wrench gets a lot of useage and earns it's keep.

I decided long ago that if I was going to do all of the mechanics on my bikes then I would need to have the correct tools to do the job. One only has to save on one repair and one will reclaim the cost of any expensive hand tool (usually that is).

You will have one problem when you are tightening the lock nuts to the bearing bolts. Firstly the torque setting is about 150NM or something like that, which is very high. Secondly you will have to somehow ensure that the Allen keyed bearing retaining bolt, doesn't move when you torque down the lock nuts.

The local BMW club has manufactured a special tool which allows us to do the job correctly. However I think that if you torque the 7NM bolts then mark the swingarm exactly with a felt tipped pen where the bolts are situated then you can check whether or not the torqued bearing bolts have moved.

By the way ensure that you have some of the special Loctite stuff beforehand and it's a good idea to get some Acetone to totally clean the threads of the locknuts of the old Loctite, before re-assembly. Check out the male and female threads for old Loctite. A thread file (French tool) is very handy here.

This might sound like a lot of stuff but remember that when you have succesfully completed the job you will have learn't a lot about your bike and you as a bonus will have some very useful tools and consumables left over for the next job.

Mick.

 

[R Savage]

The upshot is that after a very unscientific test of riding together, whereby I rode at a constant 3,000rpm indicated and he checked his at 2,900rpm and at 4,000rpm on my bike his was doing 3,900rpm.

Another unscientific test was low speed travelling. We put our bikes in first with me leading and him following. We then let the bikes idle along in first. Slowly he caught up to me and passed. Before this change his bike in first gear would overtake mine, like a walker passing a stationery bike.

Mick.

Hello Mick,

Am I misunderstanding you or has your friend effectively reduced the revs per gear required on his bike to match the speed on yours? I thought that the idea of changing the final drive to improve first gear was to increase the revs for any given speed. Thus making each gear effectively lower.

Do you by any chance know the final drive ratio for the 1100 and 850? It is 1:2.82 for the 1150GS

Richard (slightly puzzled)

 

[Mick Fagan]

Richard, my friend has increased the revs for any given speed on his 1150.

The ratio on the 1100 diff is 33/11 or 3 to one. I'm not sure about the ratio of the 1150 but I seem to think it was 2.9 to one or slightly more, so your 2.82 could be correct.

Obviously the 850 is slightly different to the 1100 and my friend worked out that the gearbox ratios required him to fit the 850

This allowed him to have an almost identical final drive to engine ratio as the 1100 or the adventure has as standard.

All I know is that on the road for any given speed in sixth gear his 1150 is now doing more revs than before. Although it may not appear to be so, he is extremely happy about this fact.

Remember that the 1150 has slightly more power than the 1100 so the factory reckoned the bike could handle the slight difference in gearing that they gave it. In practice I don't think it really worked out how they thought it would.

Rolling throttle tests in top gear, he in sixth and me in fifth are now pretty much identical from 80 to 120 Kph. as far as time taken to go faster. Before the diff change, he always had to drop a gear to keep up with me on the highway when overtaking cars whilst I just stayed in fifth.

These are real touring speeds and where you really travel at on a long distance. Before the diff change he could be in sixth gear at a steady 100-110 Kph but if he wished to overtake or look at a hill he had to change down to fifth gear. That was liveable as far as he was concerned, but the real problem was first gear in the bush.

First gear travelling was so fast that it was almost impossible for him to idle along a track and then negotiate a bog hole or similar without resorting to slipping the clutch. It infuriated him that I would idle along quite happily on my bog standard 1100 whilst he was continually clutch slipping in the messy bits.

Mind you, the original 80 G/S idles along at a slower pace than my 1100 does!

Mick.

 

[R Savage]

Thanks Mick,

Your friend’s increase in revs for any given speed when compared with the stock final drive is what I’m anticipating and indeed hoping for.

I've discovered that I can buy Loctite 2701 direct from Loctite at the very reasonable price (not!) of nearly £30 for 50mL

Cheers Richard

 

[Mick Fagan]

Richard, I've just found out that my friend has written a piece about his changing the 1150 diff for an 850 one, for our local BMW club, I'll try and get an electronic copy so I can email it to you if you wish?

Mick.

 

[R Savage]

Richard, I've just found out that my friend has written a piece about his changing the 1150 diff for an 850 one, for our local BMW club, I'll try and get an electronic copy so I can email it to you if you wish?

Mick.

Mick,

That would be great. My email address is [email protected]

Thanks Richard