Dear David, I have installed quite a few of these new sets of Yamaha keys. Yes, key leveling, dip & backcheck will be needed....all in all a good job will require a "parial regulation" or a whole day job at the minimum if the results are wished to return to Yamaha standards. I suggest you check through the Yamaha 37 steps of regulation. I learned by the checklist, have committed it to memory and apply it to all pianos. What will be need to be checked closely as well is the hammer height, hammer level, letoff, drop and aftertouch. Damper lift from keys will also be different from the original set. Yamaha has been very good at paying the full price for your work, so it does pay to do a good job even if the owner plays with his bootheel (i.e. M.G.). The response of Yamaha conservatory grand series is really a delight to work with and makes going the full nine yards a lot of fun. Best Regards, Lorlin B, RPT
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