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New tires become suspension rebuild+...(Monza) FAC update!

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SED:
The steering head bearings have a bad reputation so the triple tree yokes had to be pulled to check.  Until the late 1980s (I think!) small blocks ran loose ball bearings rather than tapered roller bearings like modern bikes.  These bearings have a reputation for early failure but these were not terrible.  Lower race in the head tube looks OK:


Strangely the upper race is in the worst condition because the track for the balls was chromed!  This picture shows chrome flaking from the bearing surface.  Why would they chrome plate a bearing surface?!  :P


Polished the inner races and bought 44 new balls.  I measured the balls at 0.1875" (3/16").  I expected them to be metric!


With the triple clamps out I decided to remove the steering lock because I didn't have a key for it.  Pry the brass rivet out using a strong knife blade as a wedge, pull the cover, then use a large punch the diameter of the lock cylinder to drive the lock cylinder in about 3/8".  The pin that holds the lock cylinder will be sheared and the lock removed by pushing it out - not in (good info here: http://w6rec.com/duane/bmw/lock/)


After the lock cylinder was removed I used a dremel to cut a slot in the sheared pin and removed it.  It was easy to replace with a short length of 3mm bolt.  I also pulled the cover off the lock pins (tumblers?) - they are tiny!  Much smaller than household lock pins. And the springs are tiny and fly everywhere.  There are 5 pins (the BMW site says 4) and I removed one, filed one and made another and was able to rekey the lock so that it uses the same key as my LMIII but with 4 instead of 5 pins.  I now have a key!   ;-T

balvenie:
SED,
      Removing my fork tubes is accomplished by driving wedges into the gaps in the triple tree. The gaps are closed with pinch bolts to hold the tubes securely. With the gaps spread, twisting the tubes one way, then the other, liberates the tube quickly. That's my bike anyway.
      With your bike being 34 yo however, that might be asking a bit much if there was a chemical(?) reaction between the different metals in the tube and triple tree. glad you did not have to hammer the axle :o ;D   

Chuck in Indiana:

--- Quote ---Removed the instrument panel so I don't bash the speedo too:
--- End quote ---
;D ;D
And yeah the balls are 3/16". Surprised me, too.
Nice tutorial.. ;-T

Tobit:

--- Quote from: balvenie on March 26, 2015, 04:16:21 AM ---SED,
      Removing my fork tubes is accomplished by driving wedges into the gaps in the triple tree. The gaps are closed with pinch bolts to hold the tubes securely. With the gaps spread, twisting the tubes one way, then the other, liberates the tube quickly. That's my bike anyway.
      With your bike being 34 yo however, that might be asking a bit much if there was a chemical(?) reaction between the different metals in the tube and triple tree. glad you did not have to hammer the axle :o ;D    

--- End quote ---

 :+1

The condition is called Shipwright's disease.  Can't put a new part on a grungy old part.

Bashing the axle would be a good way to possibly damage the fork slider or the damper cartridges.  Brute force should be reserved for Caterpillar D9 maintenance.  Nice write up though.  I miss my Monza.

 ;-T

Tobit

Groover:
Thanks for posting the steps on rebuilding the forks. It all makes sense now!

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