fast repetition

[Bradley J. Smith]

I have thirteen customers with Yamaha  MX100 II.  The advice about lost
motion is
right.   You're sure there is no excessive key friction.  And, it seems
logical that less hammer spring tension would allow the hammer to stay
closer to the string between blows.  You have adequate jack spring tension.
 I would look at combination
of checking distance from strings, backcheck angle, and key dip.
Also, be sure the pianist is sitting high enough on the bench.  Lazy
fingers won't let
the key all the way up before re-striking.  Also, check all glue joints in
hammer/shank
assembly.  Hammer shank, hammer, and especially catcher shank.

By the way, I have found Yamaha to be very supportive.  I would not
hesitate to call them.

Brad Smith
Manchester, NH