CO-ABC Tech Class on Spline Lube and Swing Arm Bearing Replacement

I’ve been hosting tech classes for the Colorado Airhead Beemers Club using my small workshop, affectionately called “Brook’s Airhead Garage”. If you live in Colorado and want to join our Down To Meet group, click here and join.

–> Colorado Airheads Beemer Club (CO-ABC) Down to Meet Site

It is a way to help disseminate knowledge about the care and feeding of these 40+ year old motorcycles. I’m hopeful that the more our members know, the more inclined they will be to do their own work, and the longer these motorcycles will keep running.

Last Saturday, one of our members, Chris, brought his 1974 R90/6 in so he can learn-by-doing. We had about 10 others come to lend a hand, kibitz and hang around with like-minded folks.

I wrote up a check list for Chris on how to do this work.

Transmission Spline Lube & Swing Arm Bearing Replacement

Transmission Removal, Lube, Install

  1. Remove air intake tubes and carburetors (leave cables on carbs).
  2. Remove air box clam shells and air filter (leave choke lever connected)
  3. Remove battery
  4. Remove battery box
  5. Remove drive shaft bolts (4)
  6. Remove luggage rack (if attached)
  7. Remove rear brake rod
  8. Remove rear wheel
  9. Remove shocks (not needed if all you do is a spline lub)
  10. Remove drive shaft front nuts (4)
  11. Remove swing arm pivot pins
  12. Remove swing arm
  13. Remove transmission bolts (3) and nut (1)
  14. Slide transmission off splines (protect frame tubes from scrapes)
  15. Inspect & clean splines
  16. Lube splines with Honda Moly 60 paste (or Honda Moly 77 paste)
  17. Slide transmission back on splines
  18. Attach transmission bolts (3) and nut (1) & torque

Swing Arm Bearings Removal

  1. Remove dust caps
  2. Remove inner bearing race
    1. Inspect for brineling to outer race and/or damage to inner race
    2. Replace if necessary
  3. If replacing swing arm bearings, pull outer races with Cycle Works bearing puller.
  4. Install new outer races with Cycle Works tool
  5. Pack inner bearing race with red LP-2 grease
  6. Install inner bearing race
  7. Install dust cover

Swing Arm Installation

  1. Install swing arm pivot pins
  2. Install drive shaft bolts (4) to transmission output coupling
  3. Center swing arm
  4. Torque swing arm pivots and lock nuts
  5. Recheck swing arm is centered

Final Assembly

  1. Inspect rear drive splines. Clean and lube with Honda Moly 60 or Moly 77 paste.
  2. Install rear drive on swing arm with new gasket and (4) bolts and washers and torque
  3. Install shocks and torque
  4. Install luggage rack (if used)
  5. Install rear wheel and torque nut
  6. Install rear brake rod and adjust rear brake
  7. Install battery box
  8. Install battery
  9. Install air box filter and clam shells
  10. Install carburetors and inlet air tubes

It took about 6 hours to complete this work including a pizza lunch and the general banter that takes the place of wrench twisting at these gatherings.

4 thoughts on “CO-ABC Tech Class on Spline Lube and Swing Arm Bearing Replacement

    • Hi Dom,

      This “short-cut” method will get you about the width of a tooth brush plus a couple fingers between the clutch bell housing and the front of the transmission. You can dab a bit of Honda Moly60 (or Moly77) on part of the length of the splines, but not the entire length.

      BTW, if you are not careful, you will put to much Moly on the splines and risk having it end up on the clutch plates, so you need to be miserly in the application. But, you don’t have much room to maneuver, so it’s easy to get too much on the splines.

      IMHO, the short-cut method is better than nothing, but not as good as access to the full length of the splines and doing a good cleaning and lubing of the entire length of the splines.

      The short-cut method likely saves about 1-1.5 hour overall compared to removing the transmission. The additional steps to transmission removal with my estimated time are:

      REMOVE:
      -Battery (5 mins)
      -Battery Box (5 mins)
      -(4) Drive Shaft Bolts (10 mins)
      -Rear Wheel & Brake Rod (5 mins)
      -Top Shock Bolts, Lay shocks down to Rear (5 mins)
      -Swing arm With Rear Drive (2 min) [You can do this and save a gasket and removing (4) rear drive bolts]
      -Remove Transmission From Frame (1 min)
      TOTAL TIME: About 35-45 mins.

      INSTALL:
      Reverse of above
      TOTAL TIME: About 1.5 x REMOVAL, or About 45-60 mins.

      Best.
      Brook.

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