Having the jack reset when the damper pedal is released indicates that the wippen needs the damper lever spring tension to force the front of the wippen down. Tight balance rail holes would restrict the key from returning efficiently. Yamaha is usually pretty good in the balance hole height department but they might need easing. The key bushings might be a bit snug as well. Is there buildup at the base of the pin? Yamaha usually uses back lead so the key might not be front heavy which would tend to cause 'sluggishness'. Some American oldies sometimes develop problems because the damper spoon wore a hole in the lever felt. -- Regards, Jon Page
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