Jay,

  The 20B utilizes a split shaft.  You're going to have to separate it in
  order to disassemble the engine.  Bob Darrah built a splitter tool from a
  threaded shaft and a 1" thick bar of steel.  The threaded shaft will need
  to
  match the threads in the #1 lobe on the crank, 18mm if I recall
  correctly.
  Thread the shaft into the lobe, slide the 1" bar over the other end of
  the
  threaded shaft until it fits snug against the nose of the eccentric, put
  a
  nut on the threaded shaft to tighten it all down.  You may want to use a
  soft aluminum or brass spacer so you don't bugger up the end of the
  eccentric.  Tighten the nut until it cocks the 1" bar a little, then tap
  the
  other end of the bar with a hammer and it should come right apart, at
  least
  that's how it has worked for me twice.  Now you can finish disassembling
  the
  engine.  Remember the sequence for when you are ready to re-assemble it.

  Mark S.


 Mark--do you have a photograph of the 3-rotor eccentric separation tool
 installed on the eccentric?

 Steve Beckham

Steve,

Yes, see the last picture in the group.  The TR (threaded rod) screws into
female threads in the #1 lobe (the removable one).

I should have mentioned that the picture doesn't show the BN (big nut)
that gets threaded onto the other end of the TR.  The purpose of the BN is
to lock the BB (big bar) down against the end of the e-shaft.  I recommend
you put a piece of softer material (like aluminum or brass) between the BB
and the e-shaft to keep from damaging the threads.

Once it is assembled, you take a BH (big hammer) and smack the unsupported
end of the BB.  The #1 lobe should pop right off.

Mark S.