Yamaha keys are: 21,6 mm
f.i. Roland,Kurzweil or Gem keys are: 22,0 mm like a real piano.

So the Yamaha keys are a little narrower.
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Keyboards/Sound Units: Kurzweil 2600S, Roland VR-760, Acces Virus C, Roland G-800, Akai AX60, Minimoog, Machine Drum, Roland R8-M, mediastation x-76