Clutch Carrier replacement

[Tony Smith]

At my usual snail's pace I now have the trans out of the bike and old clutch carrier off.

Firstly a view of the inside of the bell housing - not too shabby really since the last person to look in there was the Romanian assembly line worker in 1984, but note the "machining" done by the rivet heads as they parted company with the ring gear.

If anyone was harbouring the faint hope that they might be able to re-rivet the ring gear to the clutch carrier - think again..... Those holes are FUBAR, besides my crappy camera didn't show it, but the ring gear is cracked anyway, something I suspect is a natural and indeed likely outcome of being afforded less and less support as the rivets fail over time and finally being flung about inside the bell housing rather violently when the last rivet fails that then allows lateral movement. I also now know with certainty what the noise I could hear was .:-)

I have a nice new clutch carrier all ready to go. Here it is complete with dome red dye marking for the timing marks. What a pity I did the newbie trick of forgetting to put the crank in a known position before using the air wrench to remove the clutch carrier retaining bolts. Oh Well, ten minutes work to find TDC on compression stroke on the LHS cylinder will fix that, but it is time I could have saved.

lastly, front of gearbox, the filings can be ignored, we know where they came from, but remarkably clean given it has been undisturbed for 31 years.


Now off to buy brake cleaner and kerosene - I will be fitting a new front seal to the gearbox (the rear I am going to leave as it is still oil tight and is actually easier to do on the bike if it does need to be done), new rear engine seal, new O rings for the oil pump and clutch carrier hub, new flywheel bolts and new drive shaft coupling bolts. The clutch pack bolts and oil pump bolts I won't replace as they are not torqued that high for their size, but new star washers for the clutch pack.

I should have bought a new clutch diaphragm, but the old one will have to do now.

[Terry]

Hi Tony,
Do you need to check the run out of the clutch carrier?
if so what is the limit?
cheers
Terry

[Tony Smith]

Hi Tony,
Do you need to check the run out of the clutch carrier?
if so what is the limit?
cheers
Terry

Terry no you do not need to check run out on the carrier, its a fairly substantial pressing and was balanced at the factory. Absent mechanical damage  it isn't going to develop any nasty habits.

I should have taken a punt and ordered a new diaphragm, I didn't so i get to wear that one.

[Tony Smith]

I was not looking forward to cleaning the inside of the bell housing and the front of the gearbox. I hate nasty dirty jobs that require the application of elbow grease and time.


Someone, Snowbum I think, said use brake cleaner. So i went to my local Auto Bahn and purchased two spray cans of their "home brand" brake cleaner at $4.99 each and one can of Threebond brake cleaner at $9.99. I avoided even looking at the CRC product at $17.99.


When I got home I sprayed a little of the Threebond on the RHS and the "cheap and cheerful" brand on the LHS, the cheap stuff cleaned just as well as the Threebond and in less than 10 minutes and expending a can and a half, the bell housing is now clean enough for me to take the oil pump cover off and change the crank O ring and seal. I will spend (moderate) amounts of money any time to avoid having to use elbow grease. Tomorrow I'll buy another couple of cans to clean the gearbox with and keep at least a can "in stock".

I'm also going to buy a pail of "rust begone" to soak the diaphragm, pressure plate and driven plate in so that I can give the non-working bits a good coating of gloss grey "killrust" paint.

[Mike V]

Tony,

Brake Cleaner works well and quickly in the bell housing.  No fuss and limited labor involved.  When I cleaned up my carrier parts I used a soft wire brush on the power wheel.  Cleaned up nicely with no damage at all.

Are you sure you don't want to replace that rear main seal while in the neighborhood?

http://tinyurl.com/nuyfanj

http://tinyurl.com/nqrondh

http://tinyurl.com/o49sady

-Mike V.

[Tony Smith]

Mike I was *always* going to replace the rear engine seal and oil pump O ring. It is the rear gearbox seal I am going to leave alone on the basis that I have done a few and have run into problems again and again with the morse taper on the output shaft, usually involving hours of work with jeweller's rouge to remove high spots  and Russian blue to check the contact area.

I *HATE* going near the rotten things and curse BMW every time I need too (given that they did not hesitate in other areas, why didn't they just use a splined coupling for God's sake?).

[Mike V]

Mike I was *always* going to replace the rear engine seal and oil pump O ring. It is the rear gearbox seal I am going to leave alone on the basis that I have done a few and have run into problems again and again with the morse taper on the output shaft, usually involving hours of work with jeweller's rouge to remove high spots  and Russian blue to check the contact area.

I *HATE* going near the rotten things and curse BMW every time I need too (given that they did not hesitate in other areas, why didn't they just use a splined coupling for God's sake?).

Ahh, my retention deficit disorder strikes again (RDD).

-Mike V.

[montmil]

Ahh, my retention deficit disorder strikes again (RDD).

-Mike V.

That well-used excuse also fails the test with my bride.

[Tony Smith]

Don't sweat it - I resemble that remark!

[Tony Smith]

Well, the old girl is back together and has had a successful 10km test ride. Photos of a few relevant things when I get home tonight.

Firstly, On the basis of how the bike is now running I know that the ring gear was a long term slow failure, the thing is amazingly smooth.

Secondly contrary to my initial thoughts, the gearbox has been out of the bike before (for a new clutch plate, the one I removed has only minimal wear) the big giveaway was that the MPO (or the moronic previous mechanic ("MPM") had assembled the clutch components with the BMW factory paint marking all in a nice neat row... After carefully eyeballing everything and doing so in-depth cleaning looking for other paint marks, I re-assembled everything with the paint marks spaced out 120 degrees from each other.

The second indication that someone has been in there before was that the little flat disc seals are missing from the swing-arm, I'm not overly worried about that as I pump a bit of grease into those bearings every service anyway and Moly grease is an effective water seal.

The input shaft spines are not in the best of condition. Does anyone know of a repairer who rebuilds them, or is the breathtaking expense of a new input shaft in this gearbox's future?


And lastly. I have a huge piece of good news to share I fitted a brand spanking new drive shaft boot in around 2 minutes flat. A freind of mine who is a recently retired surgeon gifted me a moderately large supply of forceps, clamps etc - some are straight, some are at various other offset angles.

Let me tell you that surgical forceps are the bee's knees for pulling a new boot into position. It would have taken me even less time except I had to get comfortable with the lock/unlock system on the 45 degree offset forceps I was using.

Many of these beautifully made instruments are marked "single use only" so I suspect that an approach to any friends in the medical industry could net a small cache of them, alternatively they seem reasonably cheap on fleabay.

[georgesgiralt]

Tony,

When you post pictures, could you include one of the most useful forceps you used ? My swingarm boot is due renewing ....
Thanks in advance !

[Tony Smith]

Tony,

When you post pictures, could you include one of the most useful forceps you used ? My swingarm boot is due renewing ....

Your wish is my command..

My retired sawbones friend tells me that these are actually called "artery clamps". The photo shows a "straight" and a 45 degree offset clamp - in my opinion the 45 degree offset ones are more useful for the driveshaft boot job. I used a "ring" of 5 clamps and just gentyl eased the boot into position and then whipped off the clamps and installed the standard screw band - took all of 2 minutes.

I looked in eBay this morning and there are a lot available at reasonable prices. Contrary to my normal view on the costs of anything medical, you can in fact buy brand new ones for around $10 - maybe something to do with them being "single use".

[Tony Smith]

I should have mentioned in the previous post that the two objects to the right of the clamps are the mortal remains of two of the former ring-gear rivets. I lost two in a bit of a mid-operation cleanup and I've left one embedded in the bell housing as it resisted my attempts to remove it, so there is only one unaccounted for.

[Tony Smith]

Some random photos along the journey.

You can see how I removed the main seal - using sheet metal screws and a claw hammer.

The next photo is of the new flywheel and clutch re-installed, I was surprised to find that the last person to have this apart simply lined up the factory paint marks and didn't stagger them at 120 degrees as required. I know that a clutch job was beyond the Moronic Previous Owner so I have clear evidence of a Moronic Previous Mechanic.

Once the clutch was back in and centred I turned my mind to the gearbox. Again I note that I am not as neat as Mike V, but hey, clean enough, new input shaft seal and spline paste ready for re-installation.

And finally, after a marathon day in blazing heat (it was 31 degrees under our house), job done - except that I forgot the engine front cover.....

Took it for a test ride and all is as it should be. I am ramping up the IRAN process on things I let pass when I got the old girl running again, wife and I are planning a trip to the stockman's hall of fame, then Brisbane and home again in June next year - about 3,500km on +30 year old bikes, I'd like to be confident that they will do it, hence having a second look at a few "dark corners" - next on the list new rear drive splines and rear wheel drive cup.

[Mike V]

Tony,

I've found after doing two rear main seal replacements the screw thing may not be necessary.  I used screws on the R65 but found the seal came out quite easily.  While helping with an R75 RMS we were able to pry and pull with some needle nosed pliars - the seal out ... carefully not to score the case bore.

Did you notice resistance worthy of screws when you removed yours? Or not?

Curious.

-Mike V.