Did you tighten the clutch nut whilst checking the clearance , or just use  a mallet to get the basket

onto the ouptput shaft splines.

BMW only supply two washers anyway, I think the 1.25 is to allow the seal to sit 

on an unused part of the shaft.  I left my seal protruding slightly with the 1mm washer, you get the same result 

either way.

My damper housing does not contact the gear housing when fully pushed together, so the need for

a thrust washer is confusing. BMW do not show one, but everybody else does.

BMW states that, if there is excessive engine noise,  file away part of the annular spring tang, or in my case, 

one of the spring pin holes, to reduce the tension, and therefore increase free play between the gear sets.

So...you make thousands of these engines, BUT you may need to strip the bugger down and attack 

it with a file to make it quiet.

Engineering ...really.

Of course, in order to do this , you need to  check it before removing the upper sump casting,

and even then, you only get a small view of it behind the crank.

Things can only get better , or quieter.

I have ordered some moly spray for the gear sets, so in about a week, when swmbo stops giving 

me other jobs, I can start assembling the gearsets and check the movement of the backlash gear

and spring.

 Then I will refit the shaft in position, supported by cargo straps, and  attempt to check the gear free play as per

 the bulletin.  Fingers crossed I can keep the file  in the toolbox.

Finally... 

The output shaft needle bearing outer casing has an oilway , given that there is no oil gallery feed from the

 bearing upper housing, I presume to fit the bearing with the oil hole at the bottom, for splash feed ??

Bob

I think you might be over thinking things a bit,  understandable, it's a bloody tricky bit. Prob not the only one.  Basically,  simply go by your workshop manual. Don't bother with the moly reference you possibly saw on the net,  don't believe everything on the net ( including me, by the way as I'm not a mechanic,  I'm a carpenter and havn't done that in years either. Consider my posts on their merit only) 

I don't think you have the problem of the spring too strong, or you would have had it from the beginning.

I don't remember having the damper housing problem. Maybe the new rubber dampers makes it tight as. To check the thrust washer clearance, temporarily remove the rubber dampers and thrust washer. Hold the shaft vertical,  place the clutch housing on,  don't install the clutch nut, measure the clearance with feeler gauges.

Relocating the seal is not the same as relocating the shaft by installing a thicker washer,  as that increases the pressure on the absorber. I've posted something a little similar on a recent thread by tinyspuds,  I'll delete that too. 

Earlier, I typed output shaft into the search box and found endless hours on this by people who know way more than me about it.  I'm thinking all the answers might be back in there somewhere, but I might be over thinking it. Again, I'd focus mainly on the workshop manual.

Thanks to my tool maker neighbour for the loan of his lathe chuck, this is making light work of reducing my shim 

down to the size I need for the lash gear.





Finally starting the rebuild tomorrow.

Hang on! 

How about the thrust washer clearance.

Then I'll let ya focus on the workshop manual,  only cause I'm feeling generous.

audibob wrote:
The output shaft needle bearing outer casing has an oilway , given that there is no oil gallery feed from the

 bearing upper housing, I presume to fit the bearing with the oil hole at the bottom, for splash feed ??

Bob

there is no splash feed ... so stop thinking that

it is fed by the waste of the small gear shaft and bush arrangement (under pressure ) from the oil pump

the oil hole is for different applications

To the rider who asked for more about the thrust washer, this is what I see, in theory, when looking at the drawing:

With the thrust washer removed, let's say the thrust washer clearance is 0.7mm (to keep the maths simple) Then you remove the clutch housing, install a 1mm thrust washer and reinstall the clutch housing. The clutch housing has now shifted 0.3mm to the left, so there's an 0.3mm gap between the clutch housing and the spring housing.

When the clutch nut is turned with a torque wrench,  let's say after a quarter of a turn, the output shaft is pulled about 0.3mm to the left,  closing the gap,  and the diaphragm spring is compressed by 0.3mm. At this point,  let's say it's 15 ft/lb, some of this is consumed by the clutch nut, since it's also a lock nut. As the torque wrench continues turning to its destination, the friction on the diaphragm spring is not increased since the gap is closed, but the pressure on the components between the clutch nut and output shaft shoulder is, until the torque wrench setting is met. 

If a 1.5mm washer were used instead, the diaphragm spring would need to be compressed 0.8mm (almost tripple) before the gap was closed.

Has anyone found this thrust washer on their bike whilst removing their output shaft.

Both Haynes and K100rt pages show it., item 10 on the diagram below




There are marks on my end plate  (no.7) behind the shock absorber inner shaft  suggesting some movement 

during running. Could this produce the noise I hear ?  it might do if the clutch nut was not tightened sufficiently.

I can rotate the end plate, even when I tap down on the shock absorber  with a rubber mallet.



I am trying to understand the reason  for the washer .

Even without a washer, and  with the cushion rubbers in good condition, there is no room 

for rotational movement, unless the bike has done a zillion miles.

Perhaps the thrust washer allows the  shaft to exert sufficient force rearwards onto the end plate to prevent 

rotation.



I am trying to work out whether the noise got really noticeable after I put a new timing chain 

and clutch in.

I made a mistake of reusing the clutch thrust washer, and the more I think about it,

I may have mixed up my lb and nm whilst tightnening the clutch nut.

140 and 100 I remember setting torque wrenches to, but I wonder whether I set them to the wrong 

numbers. the clutch nut was certainly tight when i tried to remove it, and the washer it does look worse 

for wear.

So, what could happen if I did overtighten the clutch nut..

Tightenening the clutch nut pulls the inner cush drive towards the inside of the cush housing.

This acts upon the lash gear set , shim,  which  in turn, sits on the  inner race of the large bearing,  whilst its

 outer race is secured by the locating slots in the cases

Would too much force on the nut put stress the large bearing inner race , the outer race cannot move 

but the inner might. I know the needle bearing outer race is held by its circlip at the other end..

I am talking about very small amounts of stress, but could it make the large bearing run noisily.

or produce a stress type feel in the motor.

Having read about guys doing all this work, and they still suffer noise fills me with dread.

Bob

Many of your questions have been answered, look at the replies again. 

It seems you're self doubting all over the place, maybe cause you didn't find a major obvious cause,  understandable. Never fear,  k100 forum is here. Do the rear main seal same as last time,  since you did a good job of it. I'm guessing your puller jaws were on the bearing outer race to pull the inner race from the shaft.  If the bearing is damaged, this could be the cause,  rather than tightening the clutch nut, which acts on both sides of the gear assembly.

You may also be creating a mental block for yourself, thinking you're incapable of understanding this unit,  I know I did. One day while others were watching a two hour movie, I looked at this drawing for two hours. Have a break for a few days and try again, maybe a few times. Eventually it will click. This can also be done after the job is done.

I had all the parts in the diagram, all three workshop manuals show both thrust washers. Why ask for more evidence, look inside the absorber housing, do you have the thrust washer, spring housing and it's components?

I also could not rotate the absorber with all the Tarzan grip I could muster, but me Tarzan grip no strong like belong brick engine. 

The end plate is not splined, so there is little resistance to turning. Use engine oil to install the rubber dampers (I've amended earlier post) maybe it can turn but shouldn't be loose or rattle. A worn thrust washer in the absorber would increase the thrust washer clearance. You said the thrust washer is undersize, but by how much. 

What is the thrust washer clearance?

Hi Daveyson, 

I am fully okay with how it all works and how it goes back, but when I see evidence of movement 

 on the cush drive end washer, then I need to eliminate it as a source of noise, as there is evidence of some 

rotation.

My cush housing has no washer, no 10 on the k100rt page,  I have never seen a washer , spring and its housing 

anywhere, so can you send a foto of it so I can see what you are talking about.

I presume haynes removed the washer when they stripped the bike to produce the manual,

 motobins, motoworks in the uk do not list it. 

 BMW do not show it even as a deleted item, so if you wanted one where would be able to get hold of it.

Looking at google fotos of both 6 and 12 rivet units, I can see that on the early housing, the end washer

sits flush against the housing, whereas on the later type it does not.  

Bit odd, mine has a 2mm gap with the cush inner shaft fitted inside the housing .

The clearance between my clutch basket and the cush housing is 0.45mm

I removed the bearing with my pullers, but have a new one anyway.

I am no rush to rebuild , as I love riding this bike.

Some people can put up with noises , but it ruins the ride for me, so patience is not an issue here.

Bob

Just a quick one 

Is 0.45 the clearance called thrust washer clearance in the diagram,  and measured as described?

You still haven't told us the thrust washer thickness.

The photo of the clearance between the absorber plate and the absorber shaft,  how much is that.

Hi Bob

Got couple of big days at work,  just quick one.  I don't have a computer (doing this on phone) so photos not quick or easy. 

Look inside the absorber housing, see that raised bit in the middle,  you may think it's part of the absorber housing, no, that's the spring housing, with the other bits under it.  I assumed you separated the absorber gear from the absorber housing,  appears now you havn't, good, probably don't have to. The two thrust washers are identical.

Will give better reply within coupla days.

Hi Daveyson.

Thank you.  

You have cleared up the mystery ( for me anyway ) of number 10 washer I  keep  seeing.

I have read loads of blogs about the output shaft, but no-one has mentioned the spring assembly

before. 

This has been bugging me , enough to halt the rebuild . 

I am surprised bmw do not list the spring assembly internals , not just the whole unit.

This also allowed me to better understand that tightenening the clutch nut forces the end of the 

cush inner shaft against the spring, closing the gap between the end plate and the housing.

It also made sense of your drawing......

I looked at the inside the unit  loads of times, obviously not well enough ... 

Do these spring units get weak over time. I am temped to get it out and see.

With regards to clearances,






I measured 7mm between the thrust washer and the end of the  housing so plenty of space to snug the 

end plate up tight.

My battered  "single use" thrust washer measured 0.86 and 1 .04,  .. after I really abused it....

Poor thing broke in two ....

Possibly what happens when you mix  Newtons and lbs...

I can now proceed to rebuild her , whether the noise goes away , time will tell.

Four possible issues for the noise have been found.

1. Me using the clutch thrust washer a second time.

2. Me , probably overtightening the clutch nut.

3. A small amount of wear on one spring locating hole.

4. Lash gear shim slightly undersize.

I really need to keep "me" out of the equation....

I have a bucket of new bits and pieces, so hopefull the cost will be offset by a quiet ride again.

Thanks again Daveyson.

I really appreciate your time.

Bob

Hi 

Daveyson, 

the fibre washer you drew in the cush housing , is that supposed to be a single use item.




 Presumably  the cush housing fibre washer would suffer the same abuse as the one on the clutch basket,

or is it designed to be more robust.

 Would be very interested to know if anyone has removed the unit from the cush housing.

Perhaps you could drive it out using the two holes on the main gear casting.

BMW obviously do not expect these to fail due to them not listing the internals seperately 

on the catalogue.

Bob

G'day Bob,

How's the cold, how's the garage roof, how's the wife and kids?

I'm sposing by now you've noticed the inaccuracies in the drawing, like the big gap between the absorber housing and the spring housing, simply cause I drew the absorber first and left too much room for the stuff in the middle. Spose I should fix bits like that since I've put it on a place like the net.

The thrust washer was broken! That's big news. Was it broken before you removed it, still in position, had it fallen out? Why have you given two washer thicknesses? You say it got thicker after you abused it. I can only think of a few things that get thicker after abuse, and thrust washers isn't one of them. If you tightened it to 100 ft/lb instead of N/m (I don't think you did) the extra pressure would have no effect on the thrust washer. An earlier post describes what happens when the torque wrench turns.

I don't think your spring washer has weakened, that would increase the thrust washer clearance, I'm guessing yours is reduced, if anything. Did you hold it vertical as described earlier to reduce the chance of unwanted clearances? That might explain your reduced measurement. Hopefully someone will chime in on what the thrust washer clearance should be. In the mean time maybe google it. In the mean time I'm guessing it should be about 0.66mm, but I've only ever done this once. It's times like this that you realize how handy the factory workshop manual would be. Your photo with the 2mm gap is normal and good. in post 57, second photo, you mention the absorber plate being loose. Its hard to imagine the pressed on absorber shaft coming loose, what is the gap there, measured along side the output shaft, where the gap is smallest?

Did you actually try shaking things up a bit to see if you could see or hear a rattle, with your original undersized shim?

For peace of mind, follow the workshop manuals and service bulletins, since it describes the thrust washer as single use, then replace it. If the thrust washer was broken before you removed it, I think you should separate the absorber housing from the absorber gear, then you have easy access to the second fibre washer. I think they are identical, so then you need two of them. You need to carefully drill out the twelve rivets to separate them.

I think they don't sell the parts separately, cause they underestimated the number of brick addicts who would want to pull these apart.

Does the new spring feel like it has more tension than the old one?

Hopefully we have been over thinking things, and simply the worn spring hole is the problem, like Charlie mentions.

Hi Daveyson.

Cold here in england, very miserable.

 Garage roof good, wife to be good, and as I am soon to of an age to be classed as an offiicial pensioner here in the

 uk, my kids  are long gone.......      Peace and quiet...

The thrust washer was intact when removed, but broke in my hands  showing signs of being squashed and 

splayed out on its edges.





The thrust washer clearance was done with the unit upright, it was measured carefully.

 I need to check that the spring washer assembly compresses correctly,  butting the end plate against its 

housing

I could use a threaded rod through the housing, with a  washer the same diameter as the shaft and tighten a 

nut against a socket .

If I set it to the clutch nut to the lower torque setting, I will be able to observe the action of the spring 

assembly making sure it returns correctly.

I will measure the amount of travel from rest to the tightened position.

As to the cush drive unit , I didnt think to shake it to see if made any noises.

When I mentioned the end plate being loose, that was before you pointed out that "washer no 10"

was a spring assembly. 

I now understand that the end plate acts against the shaft,  which in turn acts against  the  spring unit .

 The distance the spring assembly compresses closes the gap between the end plate and the end of the 

absorber housing.

This is my reason to compress the spring manually, to check how tight the end plate is during normal running.

Providing the action seems good, this is the last thing I need to check prior to the rebuild.

New and old springs look the same, the original showing signs of the left retaining hole being slightly worn.

New clutch rod bush and alternator dog bearing and seal are now fitted , new output needle bearing 

outer race tomorrow.

Thanks for your inputs daveyson

Bob

Question;  One of the things I don't understand,  from post 51, BMW states to file part of the retaining tab to relieve pressure on the spring. 

I'm thinking that as the teeth of the absorber gear and idle gear are more or less brought into alignment as they make contact with the driving gear of the crankshaft, so then the retaining tab is relieved from the retaining tab hole, as the spring is compressed.

Where does BMW state that,  and how does that make sense? Does anyone have an explanation?

The information came from this web site 

http://www.bmw-k100rt-page.eu/manual/Engine/contentEngine.htm

Under engine/output shaft.

I presume the later type spring arrangement allowed for more pressure from the lash gear.

Can you imagine Lewis Hamilton needing a "file stop " to quieten his engine.

Wonder how many times the " Technical Adjustment " was required.

Not great BMW . Mr Honda would find it quite amusing .....

Bob

Thanks Bob, 

I've read point 14, I'll have to mull that one over.

I think they're saying to ensure there is enough clearance left for the retaining tab, after the backlash is eliminated,  but the position of the pins,  holes and retaining tab are pre determined by the manufactured parts. 

Since your not in a hurry, I'd wait a bit for a response about the proper thrust washer clearance.

I can't believe I'm suggesting a woe, when previously I was suggesting a go.

Are you talking about the clearance in post 62 foto.

 This cannot change and BMW only list 2 fibre washers, or are you talking about the one in your spring housing

diagram.

Confused a bit.

How did you come to the opinion that there is a fibre washer in the spring assembly,  is this what you expect to 

be used, or have you seen a spring unit removed.

Of course the majority of these later units stay in the motor for life, so never get disturbed.

I will check the travel of the spring today, and then its time to prepare to put it all back over the next two 

weeks.

One final question, what lubrication did you use on the cush rubbers to get them back in.

I could not get the shaft back in with three of the old rubbers, never mind 5.

Bob

I've only pulled the output shaft out of one engine, maybe wait for a bit for some other input.
I separated the absorber gear from the absorber housing, by drilling the rivets out. The two fibre thrust washers looked identical to me, they were both 1mm thick. I'm guessing from your description that the fibre washer that broke in your hand was in bad shape, but don't know how much pressure you put on it. for peace of mind, since you came this far, I would consider replacing both washers. For all we know, maybe your second thrust washer is broken too, you haven't seen it yet. Previous posts also give the book and page number, with a diagram that shows the spring housing and its components. It doesn't make sense to have a thrust washer on only one side.

In post 62, your photo with the 0.45 clearance is the thrust washer clearance in the diagram. This clearance can change, as explained in earlier posts. Your clearance is reduced, compared to mine. This, I think means that your thrust washers are under increased pressure, compared to mine, which I will guess is the reason it broke easily, not because of the clutch nut torque, which you blamed yourself for. This is a wild guess, I didn't see it break. I'm assuming the thrust washer clearance should be about 0.66 because mine was, this is also a wild guess.

Read the post again about what happens when the torque wrench turns, and you will see that your pressure is seriously increased, compared to mine, if I'm interpreting it correctly.

If in your position, I would pm one of the experienced members here, if you don't get a response soon. I've got help here a few times with pm's, I didn't even know how to post a photo, until this thread. They are a great bunch of blokes here, and women, and I'm very greatful for the help I've got.

Use engine oil for the rubber dampers, that's what they live in. I had no difficulty pushing the absorber together, but I didn't use new rubber dampers, maybe you need to press them in. Previously I said I didn't have a problem with the rubber dampers to measure the thrust washer clearance, but it has come back to me now that I did remove them, on the second occasion, after being measured twice, now I'm struggling to remember, why twice.

There is a good chance that 0.45 clearance is fine, and simply the worn hole is your only problem, I don't know. Hopefully that is the feedback you get, cause that would simplify things a lot, and I'm overthinking it. Hopefully your response comes on this thread, cause then I'd find out too.

Again, I think your plan of attack is good, you're putting a whole bunch of new stuff in, that's got to be good.

In the previous post I defeated the strong urge to say that the thrust washers were almost identical, with the clutch housing thrust washer being the more identical of the two.

audibob wrote: You have cleared up the mystery ( for me anyway ) of number 10 washer I  keep  seeing. I have read loads of blogs about the output shaft, but no-one has mentioned the spring assembly before. 
This has been bugging me , enough to halt the rebuild .

Here is another approach for dealing with this blasted spring assembly.

The  infamous washer ( no.10 ) as shown on many manuals.



A brief description , what it looks like in real life, and how you need to muller the rivets to remove it

would have been helpful..

Thanks for finding the foto Laitch. 

Daveyson, did you replace your fibre washer with a new one whilst repairing your rivets.

So, if you swap an old unit for the later type, the purist ( not me ) would recommend removing 12 good rivets to

 get at one fibre washer  Cannot see that ever being  done, especially by me . I will stick , not twist...

Bmw obviously did not expect anyone to want to replace it , or perhaps see the need to change it.

Looks like a concave type spring doing the work.

At least I now know what lies below...

Time to get down and dirty first thing Monday morning 

Thanks guys, this has been very interesting

Bob

Bonus, good find Laitch,  that's paydirt right there. 

Sink your teeth into that Bob. 

I'll have to read that too, down the track.

You don't want to replace the thrust washer. That reminds me of the bloke who swam three quarters of the way across the lake, and knew he couldn't get to the end, so swam back again. You've done the hard yards, do the easy bit. Consider a bolt shop, he might say here's the rivets and here's the tool, or here's the place that does it. Or here's some bolts to suit, simple. Or a local rebuilder. 

The engine I took apart is still in pieces.

Background:
I have five bricks,  four normal,  and then there's blacky. She's black. She has weirdness all over the place. When I finally got it going, it had a deep, low down knock.  I was worried about it going bang. I was lucky to score an engine in good nick for $50. A mini driver took the head. Did you know in Australia a mini driver will happily pay $200 for a k100 head! Because it fits a mini engine! And converts it to overhead cam! So they win the mini races!

So I was going to swap the output shaft. The local BMW bloke said the sound was a classic case of hardened rubber dampers in the output shaft, since it quietened down after say twenty minutes, as the rubber gets warmer and softens. 

His given opinion was that they are still absorbing, but say half as much as when new, so causes no damage, but if it fails, is reparable. From Charlie's post,  I gather that refers to the rivets. He said if you don't mind the noise they can go for years like that, if it doesn't fail, don't fix it,  if it fails, fix it. 

I like the noise. I love the sound of Ducatti's ridiculous multi plate dry clutch. I'm very easily convinced if someone tells me I can strike something off my "to do" list. But I couldn't help myself, so I pulled the output shaft out of the new engine, and now consider it spare. 

Background to Blacky:
She was born white, policewhite. I wanted to call her bluey,  on account of her being black, but I already had a blue one I called bluey,  so I had to call her blacky. One example of it's black magic weirdness, it ran without a fuel pump. There's an old thread about it, recently revived.

Daveyson, 

An accurate analogy... sink or swim....

What was the condition of the spring assembly thrust washer you removed.

Caught between a Rock and a hard place at the moment.

 Yes replacing it would be best, but each time the clutch nut is removed and then retorqued , the "Spring 

assembly " thrust washer is being "reused"..

Would like to believe BMW designed the fibre washer strong enough to withstand at least one re-torque

 of the clutch nut during its lifetime.

I cannot see anyone removing  12 rivets  to replace it, as I guess the majority like me do not know there 

is one fitted .

Would anyone know what the 12 rivet hole diameter is...just asking....seeing as there is no need to 

put larger bolts in .

Has anyone got their 6 rivet unit in bits at the moment and are willing to post fotos and measurements 

of their thrust washer , and how many times the clutch nut has been retightened.

That would be very helpful.

I wanted to call my current k Daphne , but my other half said no....

Bob

I havn't got that engine at my place,  so not easy to get to.  Try a drill bit, say 80% of the rivets peined head,  take it easy,  you will soon find the diameter.

Both thrust washers I removed looked in perfect condition.

I wouldn't call the thrust washer used just because it was tightened once,  I don't think the service bulletin is saying that.

I admit I haven't read all the service bulletin or the thread from Laitch, but I will get through that thread. I might change my opinion after that,  but for now,  if I were in your position, I would take it to a bolt shop with the hope that they say to you "here are the rivets and here is the rivet tool"  simple. And you will say, wow that was easier than I thought. If no luck first, try a few bolt shops. 

I like the idea of rivets rather than strong bolts, if there are excessive forces,  I would rather have rivets break, than the absorber housing, but I spose the forces aren't great and both methods work.

I'm not good at refining searches,  in your travels, have you found any posts stating the thrust washer clearance, for comparison?

........hmmm......... 

OK...... Right... . 

Another confession.

Give a chippy an option between a hammer and a torque wrench and it won't be too hard to guess which one he chooses. Could be another reason I like rivets.

The cush rubbers are finally in place .  I used the clutch nut thread to pull them in most of the way, then fitted

the clutch basket with its collar, and tightened the old nut to achieve a 2mm gap as seen below,

 the inner cush drive shaft is now just touching the  "infamous and hardly seen" spring housing . 



I used a rubber mallet  on the output shaft at the needle bearing end to make sure the cush  end plate was

 acting against the inner shaft whilst turning the clutch nut. 

The spring assembly will compress and close the gap when the nut is torqued, If I remember correctly, you can

 see the end plate through the gaps in the crank assembly.  

The 2mm gap 




This is my " bodge it and scarper " tool for checking free movement on the lash gear .




As I am working " down under" I have fitted guides to ensure at all goes back up evenly, one , to ensure

the sealant does not wander off anywhere it shouldnt, and secondly that the needle bearing circlip feels the " groove"




Tomorrow the shaft goes back in along with the upper sump casing, then I will leave all the gloopy stuff

to set over a couple of days before getting the jack back under the sump to refit the intermediate housing.

Then I intend to oil the main bearing and  fill the output shaft with as much as it can hold, before 

refitting the oil pump.

Once everything is back together, with fuel disconnected ( obviously ) run the starter motor for as long as 

I dare before killing the battery.  And then start her , and hear (or not  hopefully ) the rewards of 

my endeavour

New parts fitted.

 Main bearing and circlip.

Needle bearing and its outer race

Cush rubbers.

New cush gear shim .

 1.5mm shim from the packet, reduced to 1.43 to give me 0.07 clearance. via the heath robinson tool  as in my

 foto.

New cush gear spring, old one has slight wear on one hole

New 1.0mm Clutch basket thrust washer, o ring  and nut

Rear main seal 

 I did not renew the " Famous " spring housing thrust washer


As George once sang... you gotta have faith..

bob

Good luck. 

I probably was over thinking it about the thrust washer clearance. Yours is a different model, they could have easily decided to allow more pressure on the absorber. What's 0.2mm amongst friends anyway? But still,  did you find any other references as to what that clearance is supposed to be?

I guess the possibility of having to strip the motor down to ( hopefully ) fix noises fills most owners with dread,

and annoyance that BMW cocked it up....

Would I have bought this bike knowing there is a risk of having to drop the sump to access the bugger,

Yes....

Fortunately I love riding her enough to put up with being off the road for a while.

Have I enjoyed the experience... yes . 

Would I have preferred to do the job with the motor out , possibly , but being fortunate enough to have 

a bike lift, and an RSJ in my garage roof meant it was manageable to do it in situ.

The down side is have to support the bugger with straps whilst refitting the upper sump, 

definately easier doing that with the motor out.

Of course the worst aspect of doing this job is keeping your fingers crossed whilst firing up the motor,

wondering whether old noises have been replaced with a new one.

Daveyson, 

if you are talking about the  2mm gap between the end plate and the housing,  I will be watching it when I 

torque mine up.

Bob

Nah,  I meant that the difference between your thrust washer clearance and mine is about 0.2mm

Did you find any references as to what the thrust washer clearance should be?

OK,  here's another way to understand this wicked beast of an output shaft, by following the power flow through it.

The crankshaft gear turns the absorber gear. The absorber gear turns the absorber housing, as they are riveted together like one solid unit. The vanes of the absorber housing (pink dotted lines on the drawing ) transfer the force to the rubber dampers. The rubber dampers transfer the force to the vanes of the absorber (black dotted lines) The absorber transfers power to the output shaft because they are splined together (as is the clutch housing, but not shown on the drawing to simplify it)

Under heavy acceleration for example, the rubber dampers compress under the load.  This means the gear assembly has turned more than the output shaft, even though it's only a small amount. If not for the thrust washers, that would mean sliding steel to steel contact between the absorber gear and the clutch housing on one end,  and the absorber gear and backing plate on the other end. That's why there needs to be two thrust washers.

The absorber gear is compressed between the output shaft components by the diaphragm spring,  which in turn is compressed by the torque applied to the clutch nut.  The pressure from the diaphragm spring on the absorber gear, makes the sliding contact on the absorber gear more critical.

Havent come across any info as to what the clearance should be.

Am sure I have seen Tech drawings , in German in think cannot remember where.



The bugger is finally in situ.   Not easy on your own though plenty of cussing helped.

Found this oil seal on the bike table after tapping the sump to settle everything, not sure where it came from 

or how it got there..

The top red one.

The others are the old ones 




I expect comedic replies, gremlins poltergeists etc.

Oil pan tomorrow and leave for two days to "cook" the gloop.

All down hill from here ....

Bob

audibob wrote:Found this oil seal on the bike table after tapping the sump to settle everything, not sure where it came from or how it got there. The top red one.

For an ID like that, posting dimensions would be helpful. It might be this one.

Hi Laitch, 

I didnt have time to measure it, it is not the water pump housing seal or the sump water passage seal,

which are the same size.   The small black one is the oil passage seal in the sump.

I have no idea where it came from.. 

Apart from it is cut,  it is not out of shape in any way..just very hard from age.

How it got onto the bike stand is weird , I really do not remember it from anywhere.

audibob wrote:I didnt have time to measure it, . . .

That's understandable. It's running out for many of us.

Will be sweating over replacing the dreaded main rear seal soon.

I came across a guy who put the seal on the clutch basket and wound it on .

This method I find interesting, but I would get a spare basket and drill the rivets out , dump the basket

to give a clear view of how far the seal is.

Of course removing the "tool" will disturb the new seal, but if you do not take too placing your basket back

in plus fibre washer and seal, then I think it would work.





It is such a pig to get in without it disappearing below the "plimsoll" line,  these do not come out again happily.

Any thoughts out there.....

Bob

There is always the BMW tool  11-1-630 , easy to knock up on a lathe. I can measure the outer and inner dimensions if required.

http://forum.kforum-tech.com/members-upload/uploads/88_88_6_111_630.pdf

Mike

*

One option; the way you did it last time worked. 

P.S. didn't look at that photo close enough.

daveyson wrote:One option; the way you did it last time worked.

That was the method described in Reply 8, audibob. Forward ho!

I have a vague memory that pre forming only applies to certain brands,  is that right? But since it worked, I'd repeat it.

daveyson wrote:I have a vague memory that pre forming only applies to certain brands,  is that right?

Preforming applies to Teflon seals.

The foto of my busted seal was from today..

Me being careful ......not  .

am probably not the only one.   

You go too far and its toast 

First time lucky second not..

So difficult to get very small movement via a 10lb hammer.........

Have no access to a lathe or know anyone locally, so back to brute force  and a little less ignorance..

I dreaded doing it last time , especially as how much they charge for the bugger.

No work this weekend, should be running by next .

Bob

Mathew-Brisbane encountered a problem with seals and "O" rings. Be aware that the seal lip on some of the non OEM seals run right on the edge of the seal running surface. The OEM seal lip runs further back by 2-3mm. Linishing of the running surface is advisable to give the seal lip a clean unmarked running surface. He also found a discrepancy in size of the "O" rings he had 4 or 5 from different sources and they were all different diameters. The size difference was to the point that some were buckling on fitment.
Regards Martin.

Hi Martin,

I must admit, the seals I get from Motorworks were a mixed bag in terms of how they fitted .

The small oil seal in the sump fitted really snug, but both water pump and its gallery seals looked very " lost",

but they worked last time..

I even got one water pump seal from Motobins, but that was the same. 

Both crossed referenced the correct BMW number.

I linished the seal running surface, and the Motorworks teflon seal sits with a little room to spare




I wonder if I packed the some 50mm washers behind the seal, so the Teflon lip is clear of its running surface,

then it should wind in without disturbing the shape of the seal lip.

Or perhaps the old seal..like you do when fitting bearings

Bob

I've never used a Teflon seal and I believe none of Matts seals were Teflon. As long as the seal lip is on the running surface you should hopefully be OK. You should be able to measure where the lip will be running. Also check that the "O" ring doesn't deform when fitting.
Regards Martin.

Here's an interesting video—a wrencher using neither fabricated drift nor mallet. He doesn't indicate whether the operation was a success or the engine was spraying oil like a cropduster when the moto was underway. His heart is in the right place though, he's seems to be calm—or sedated—and the music is sufficiently evocative of piña coladas to relieve the view of the snowfield outside my window.  
https://www.youtube.com/watch?v=QtijhN7fucY

Look at her clutch video, in an attempt to moly the clutch splines,  misses and moly's the clutch housing.

Close, but no cigar.

I put my old seal in the freezer overnight, and as you would expect it was really easy to get it 3 or 4mm in the 

seal housing nice and straight.  Getting the bugger further in required more force, as before.

Being in the freezer seemed to have no effect on the actual seal lip as I slid it onto the seal running surface.

Cannot see anyone trusting this method, so I am still hankering after winding it on.

I might  try a 40x80mm bearing  (which is 10mm under the lip diameter) behind the seal ,and wind it in on the 

clutch nut.

As long as the seal is in perfect start position, it should work.

Will be interesting to see if the cush drive spring housing begins to compress at the same time, 

I need to watch the cush drive end plate to see if it closes the 2mm gap against the end of the cush 

housing .

Not sure how many times that elusive cush housing spring can be abused before it gives up the ghost,

do not fancy stripping the motor again..

In theory,, ha ha,, If you placed the 1mm thrust washer on the basket shaft, placed the seal onto its running 

surface ,and then wound it in, the seal should end be in its correct running position in its seal housing when the 

torque wrench clicks.

Is this how it was done at the factory...  

I have a 1.25 thrust washer, and my old seal outer surface is good, so I will try it.

BMW seals appear to come without the preformer from a foto I saw , not sure which type Motobins

provide. 

Seals fitted with the preformer are 48.5mm against the 50mm shaft diameter allowing minimal deflection ,

 my first seal, from motorworks I think came without, so I used a 46 mm pill bottle.

I left the 46mm pill bottle in the seal overnight before fitting.

  Had to us lube and care when refitting the basket shaft as the seal lip gave a little more resistance before 

settling on the shaft. I then rotated the motor one revolution and allowed the seal to sit for 24 hrs.  No leaks..

Of course I can fit the new seal in a matter of some careful minutes, but that would be easy ....

"Bang it in, Torque it up, and move on " I hear some say....

Bob

Quote,  Bob;  "I have a 1.25mm thrust washer, and my old seal outer surface is good,  so I will try it"

I hope you don't try it,  that would put more pressure on the diaphragm spring (and other bits) than its been designed for.

You can re torque the clutch nut multiple times without risking damage to the diaphragm spring, as it's designed to be compressed it's entire life, but not with the thicker washer.