It’s probably not necessary but I figured it would be a good idea to remove the speedometer drive.  It is held in place by one special bolt.

There are 15 bolts that secure the two case halves together.  On the right side there are 11 bolts, and on the left side there are 4 bolts.  Of these 15 bolts, three are well hidden.  Don’t miss these two bolts on the right side.

Since I was only going to inspect the balancer drive and re-seal the case joint, I left the shifter mechanism alone.  I wasn’t planning on removing the gear set.  Leaving it in place did not present a problem.

The plate with the notches and hole is used as a jack to push the crankshaft through the inner race of the right-hand main bearing.  When you back off the primary drive gear nut it pushes on the plate, which is equivalent to pushing on the crankshaft.  You also must take measures to keep the shaft from turning with the nut.  I discuss that later in this report.

I did not remove the crankshaft or gear set.  I only wanted to fix the leak and check out the balancer shaft drive.  Fixing the leak was simply a matter of cleaning up the sealing surfaces, checking for defects, and applying a fresh coat of Permatex Optimum Grey.

The three items I wanted to inspect on the balancer drive were:

-The drive key on the balancer shaft

-The drive pin in the drive gear
 
-The cam chain drive sprocket.
 
The key & keway looked fine.  No evidence of any wear or deformation.

Based on the photos that BlakeEM posted, I believe his failure was the result of overtightening the nut that secures the primary drive gear and cam chain sprocket.  The overtightening cracked the cam chain drive sprocket.  That relaxed the pinch on the left side of the crankshaft, allowing the balancer drive gear to rotate back & forth as the crankshaft went through its normal acceleration and deceleration.  The constant back & forth rotation pounded the drive pin loose.  This is just my opinion, but I think it’s based on compelling evidence from his post.
 
I examined the cam chain drive sprocket at 5X magnification.  I wanted to make sure there were no cracks in the fillet.  

I toyed with the idea of making a stepped pin for the drive gear. The step would capture the pin between the gear and crankshaft.  Maybe I could make one from a grade-8 bolt.  Checked the pin with a machinist’s scribe.  That sucker is hard as a diamond.  The scribe wouldn’t even mark the pin.  I can’t fabricate a pin of equal hardness.  Guess I will have to live with the factory setup for now.  It will become one of my routine inspection items.

Reinstalled the gears and made sure they were properly timed.  All three dots have to line up.

There should be about 1mm gap between the tool and the crank when the pin is in the correct position.  If the gap is any significant amount larger or smaller than 1mm, the pin may be moving.