She's Alive! 

by Deryle Mehrten

 

This past October (Oct 2012) Wanda and I traded in our pristine 2006 Moto Guzzi Breva V1100 on a Frost Blue/Marrakech Red 2002 BMW K1200RS.  Unfortunately for the last year or two the KRS was a trade-in Queen. She sat outside slowly being eaten away by the Arizona sun.  A serious clutch o-ring leak, along with a bit of cleaning neglect, had her covered in oil and road grunk.  She was nasty dirty and needed a new home…badly.

The 2002 KRS was the first year the big “bricks” came with linked power assisted brakes, commonly referred to as whizzy brakes.  A front fairing revision beginning with the 2002 model year eliminated the knock off mirror pods, a good move in my opinion.  This was also the first year for a real cruise-control, a set-it-and-forget-it system just like BMW’s automobiles.  The brick engine remained pretty much the same though all the model years, and is known as a robust, bullet proof flat four that develops 130 horse power and a bunch of low end grunt.  Although a bit heavy in the handling arena, they make great long distance touring mounts.  We’ve owned two previous models, a 1998 and a 2004, and are already enjoying our third.

To bring her back to life and roadworthiness, a rear main seal and clutch o-ring replacement was the first priority.  It seems a leaking o-ring problem has plagued BMW K model bikes from the beginning.  The o-ring BMW sources to keep engine oil from migrating into the clutch housing just isn’t tough enough.  Most K bikes with 40 to 50 thousand miles have an oil seep or weep around the clutch housing indicating the clutch o-ring has given up the ghost.  Over time if ignored engine oil leaking past the o-ring can contaminate the clutch.  The repair entails removing the rear swing arm (called by BMW the rear fork) and pulling off the transmission to get to the clutch and the offending o-ring.  Not a simple one or two day repair for this back yard mechanic.

With an older OEM K1200RS repair manual and a new Clymer K1200RS manual in hand (and after some extensive Google searching) I was ready to remove the rear pivot pins and take the rear drive off, the first step in the process to remove the rear swing arm.  This required some serious heat to loosen the pivot pin bolts as they were heavily torqued and Loctited into place.  The right pin came out smoothly; the left didn’t.  The left pivot pin pulled the last three threads out of the swing arm, bummer.  Seems the heat needed to keep the Loctite molten was higher than I anticipated.  I used an IR thermometer and looked for the pins to reach 250 degrees F.  I learned later that 300 degrees is the temperature that Loctite recommends for the thread locker that BMW uses.  A used rear swing arm cost us $320.  That would be my only oops throughout the renovation of the big brick.


Because I was also cleaning lots of grunk off of everything, I decided to basically strip the bike down as much as I could without breaking any of the whizzy brake connections.  This meant the combination brake pump and battery box could not be fully removed.  To allow it to tilt up, I either loosened or removed all the metal brake line mounting bolts and clamps.  This allowed the pump/battery box to lift up high enough to allow access to everything I needed to get to.  The whizzy brakes remained closed and tight throughout the renovation.

The gas tank, air box and both radiators were pulled to allow access to the front of the engine for cleaning and later to tighten the engine mounting bolts back down.  Foot pegs and their mounting plates and lots of little “things” came off and after extensive cleaning were stored in plastic bags and Tupperware tubs to keep them organized.   All the body work and panels were cleaned and hung from the rafters using old metal coat hangers.  The KRS was stripped and looking quite naked.

It was time to hang her off the rafters before any more of the rear of the bike was removed.  Up to now the bike was being held in place by the front wheel clamp on my Handy lift and the bike’s center stand.  To remove the transmission and get to the clutch I would have to lift the frame off the engine.  My scissor jack under the engine with some rags and a piece of plywood to protect the sump held the engine in place.  I loosened the two front motor mount bolts so the engine would pivot down slightly as the frame was hoisted up.  With a pair of soft ties looped around four frame bolts and a ratchet tie down looped over a reinforced roof rafter, I lifted the frame ever so slightly off the engine.

NOTE:  Loosening the frame bolts is easy - tightening the left one back down is not.  I fabricated a “special tool” by grinding down a 15 mm box end wrench to get to the left frame mount nut.  Without it I could not get the correct torque on the nut/bolt.

The swing arm bearings were relatively easy to remove.  A 30 mm ˝ inch deep-well impact socket and a 12 mm ˝ inch Allen wrench with a long breaker bar took them right out.  I popped the drive shaft off the transmission output shaft leaving the transmission fully exposed.  There was no trail of transmission grease in the swing arm and all the splines on the rear drive, drive shaft and transmission were in excellent condition.  The drive shaft universal joints moved easily with no catches.  Excellent!

Time to take the transmission off.  First I removed the gear indicator switch and the clutch slave cylinder.  The clutch rod came out easy enough and was dry, very dry – a good thing.  Pulling the transmission off is a lot easier with four drifts made from 40 mm bolts with their heads cut off.  The transmission has 8 bolts and by replacing the top four with these drift bolts the transmission slid back and away from the clutch.  The warning here is the transmission wants to hit the frame on the right side.  With a bit of pulling and pushing, and with those drift bolts in place, I managed to get the transmission off and later back on with no right side scrapes.
 

The transmission seals looked fine, although the inner seal and everything within the clutch housing was covered in oil.  The worn out clutch o-ring had obviously began to fail some time ago.  After a few sniffs I felt pretty confident the transmission seals were still doing their job.  Transmission grease has a very distinctive smell, it’s very high in sulfur. It’s easy to smell if it’s present – I didn’t.  This was another very good thing.

Warning!  The clutch is a balanced unit.  Before unbolting it and pulling it all apart, mark all the parts so they can be lined up exactly the same on reassembly.  Very important or a clutch vibration could result.

Breaking the six one-time-use clutch bolts loose was no problem.  They all came off nicely.  To get the big clutch nut off I needed my first special tool - a piece of 1/8 thick aluminum stock bolted up against the clutch and fitting tightly against the intermediate housing.  The 30 mm clutch housing nut is tightly bolted down and a bit awkward to get to.  I needed my second special tool – a long handle bolted to the clutch intermediate housing so I could get a good grip and some leverage.  A long breaker bar was a real helper.  The nut came off, the clutch housing came back and the o-ring fell out.  Hard and brittle, it broke into several pieces at the slightest touch.  It took a full day of cleaning with every solvent I had to get all the accumulated oil out of the intermediate housing’s nooks and crannies.  


The clutch assembly was…oily.  The clutch spring was all in one piece, no broken fingers.  The clutch disk had some discoloring and the rivet indentations were packed tight with old oil.  Here’s where I used some of that “information” I gleaned from searching the web.  First I let the clutch disk sit overnight in a pan of acetone then I lit it afire; next I soaked it in bucket of alcohol for several days and lit it afire again; finally I cleaned it off using a full can of spray-on brake cleaner.  It looked as good as the pictures of all the used ones for sale on Ebay.  I measured it with a micrometer and it was within spec.  I decided reuse it. 

Several weeks before I began pulling parts off I ordered a bunch of replacement gaskets, nuts, bolts, etc.  The bolts on the clutch are one time use and so is the clutch nut.  To repair the clutch o-ring leak a new rear main seal, spacer, o-ring and clutch nut are required. Rather than use the OEM o-ring I ordered a Viton branded 19x4 mm o-ring off the internet.  The Viton material is reputed to handle heat and petroleum products better.  Everything trickled in over about five weeks.

The main seal pried out relatively easy.  The new and improved seal went in with the help of a BMW wheel balancing tool.  I was careful to drive it in straight and just to the edge of the engine housing.  Next I put in the new spacer, washer and Viton o-ring.  To get the clutch nut back on I needed my biggest torque wrench and a torque degree wheel.  To hold the clutch hub in place I again I installed my 1/8 in stock aluminum special tool and my long handle so I could get a good grip.  Per both manuals I took the nut down to 140 nm, backed it back off, tightened it back down to 50 nm, and finally tightened it down 60 degrees.  All went well.

To get the clutch plate to line up with the transmission input shaft I needed another “special tool” to keep the clutch plate in the center of the assembly as the 6 clutch bolts were tightened down.  I used the OEM clutch push rod and a piece of aluminum stock that was part of the same BMW wheel balancing kit I used to drive in the main seal.  The clutch bolts torqued down nicely and my special tool held the clutch plate centered.  Time to put the transmission back on.  
 

Using the drift bolts again, I pushed the transmission up to the clutch plate splines.  By putting the transmission in high gear I could twist the transmission output shaft so the input shaft would move and line up with the clutch splines.  It took a couple of tries then it slipped right on.  I torqued down all the clutch housing bolts and felt pretty good about a job well done.
 

 

A special tool is needed to get the swing arm bearings back on and torqued down properly.  The factory tool runs about $110 so I decided to make my own by cutting the side out of my 30 mm ˝ inch deep well socket and trimming an inch off the end of the 12 mm ˝ inch Allen socket.  The Allen wrench holds the bearing pin at the designated torque as the 30 mm socket tightens the lock nut down.  Like the rear swing arm it takes some serious torque to get the left lock nut down tight.  All went well.  

Time to tap the drive shaft onto the clutch output shaft.  Before I pushed the drive shaft into the swing arm, I marked it so that it would be “phased aligned.”  The universal joints at the front and rear of the drive shaft should be aligned to prevent vibration.  I laid out the shaft and pushed the end piece on marking them both with a drop of paint.  Then I pushed the shaft into the swing arm and began the process to bolt the rear drive back on.

I made my first (and so far my only) mistake taking the swing arm off so I approached this part of the job very cautiously.  I didn’t need another costly mistake.  Rather than use the OEM pivot pin bearings, I installed a JL Paralever Bushing Upgrade Kit.  I rehearsed the process several times before I put the Loctite on the pins and lock nuts and applied the torque wrench.  The new bearings went in nicely and the lock nuts and pivot pins torqued down as they should.  Again I felt pretty good about a job well done.

From there on it was putting everything back on and torqueing it all down to factory specs.  Wanda searched the OEM and Clymer manuals for the numbers and I went from side to side and torque wrench to torque wrench bolting and screwing everything back on.  Rubber gaskets and old nuts and bolts were replaced as needed.  Fresh engine oil, transmission grease, rear drive grease, antifreeze and clutch fluid went in.  I must have gone through a hundred zip ties and still didn’t get all the wiring just right.  

While I had everything off and exposed I installed a couple of the goodies I had either left over from our past K1200RSs or that I took off the Moto Guzzi Breva before we traded her in.  OEM rear “P” lights went on along with a Back Off license plate frame with two rows of LEDs.  On the front I mounted a set of PIAAs driving lights that we bought at the MOA National in 2001.  The old gal was looking pretty good!

The one thing I decided I would not try, at least not this time, was installing new brake lines and flushing the whizzy brakes.  For that I took the bike to Iron Horse Motorcycles in Tucson.  The new stainless lines and the EVO brake service set us back a few bucks, though the difference in the brakes and peace of mind knowing all the old rubber lines were replaced was worth it.  A new battery went in at the same time.

Our first ride on our new-to-us K1200RS put a huge grin on my face.  She ran a bit rough at first and there are a few more nits to pick that I’ll sort out over time.  She’s a worthy stable mate to our 2008 K1200GT. 


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