Crank be true!

Many aspects of the engine rebuild have been intimidating, but none so much as the equally black arts of balancing and truing the crank.

I hired out the balancing to Truett and Osborn.  They have been in business since 1974 or so.  I am confident they have figured it out by now.  The work looks very thorough.  Time will tell.

For the truing, I relied on the expertise of Fuzzy Jamison, owner of Classic Thunder, a fellow Seattle Cossack, and a good friend.  I also brought BitMonkey for moral support.  We used Fuzzy's  beautifully built ($$$) Rowe truing stand. 

Here's a little theory.  I read and re-read my Revised 2nd edition copy of trusty "Motorcycle Mechanics and Speed Tuning", circa 1939.  There are three distinct ways in which the crank may be out of true (probably more if any of the parts are damaged).  They are:

 A. This first kind of misalignment will result in peak readings when the crankpin is at the top or bottom (above or below the drive shaft and pinion shafts), or very nearly so.  The "fix" involves a well-placed "rap" (or multiple raps) with a lead or brass hammer on the outer surface of the trailing wheel, more or less 90 degrees from the crankpin.  DO NOT do this with the crank in the truing stand!!

Watching someone beat on your immaculate flywheels is like watching an orthopedic surgeon set your child's femur.  Not for the faint of heart.  Get it as close as you can in this direction before going on to "B" or "C"...

Both "B" and C" will result in peak readings when the crankpin is near the same level as the drive shaft and pinion shafts.

"Motorcycle Mechanics" suggests a wedge to correct the misalignment shown in "B".  Fuzzy has ground a 5/16" nut and bolt to exactly the right length to slip in between the wheels, and he spreads them with a pair of wrenches.  Very controlled and precise.

"C" illustrates the need to squeeze the wheels at the arrows.  "Motorcycle Mechanics" suggests a vise for this, but Fuzzy used a large C-clamp.  Again, very easy and precise.  

We were very careful to loosen the dead centers on the truing stand each time we squeezed or spread the flywheels.

Eventually Fuzzy figured that Bit-Monkey and I wouldn't hurt ourselves, and left us to our own devices.   With about 2 1/2 hours invested, we got the crank to .0005" (half a thousandth) on each side.  The Indian Overhaul Manual calls for a maximum runout of 0.001.  I am very pleased!!

Thanks very much to Fuzzy and BitMonkey for the help.  I can't wait to see how it runs.