Good morning everyone, I am presenting a doubt regarding the weighting of my piano, a 1967 Yamaha CF, purchased two years ago, in excellent condition and entirely original (I say this with the critical eye of a technician, since I work as a tuner and technician): the doubt in question is that the key weighting was done very poorly at the origin, right at the factory, which surprises me somewhat, given that Yamaha is usually very precise; but perhaps the standards of precision in '67 were not the same as those a few decades later.
This doubt arises from the fact that the keyboard has a very uneven weighting (up to 10 grams difference between adjacent keys) ranging from 49 down to 35 g of static weight, with a return of 34 down to 25: it is therefore uneven, snappy, and very light—too light! Furthermore, the weights of adjacent keys are placed in quite different positions, even though the individual hammers have a rather uniform graduated weight (the difference between one hammer and another is around about 0.2 grams and the original hammer rail has not yet been shaved in 45 years). It goes without saying that I have lubricated the pins, checked the bushings, and the situation hasn't changed much.
Removing one of the weights from two keys taken as a sample, I obtained 49 g of weight and 34 of return: a value, at least for the static weight, that is excellent, even if the weight/return ratio remains well below 2, which confirms that the action was designed to be very "snappy." But aside from this design, the inequality of the weighting surprises me. My suspicion is that this was done in the factory with a certain sloppiness, without eliminating any potential friction due to new and perhaps slightly tight pins and bushings.
'67 was the year the first Yamaha Grand Piano was released on the market, designed, among others, by Tallone: is it possible that, in the challenge against the historic European manufacturers, Yamaha faltered on "minutiae" such as the good execution of the weighting of its flagship piano? It seems difficult to me, but I have no other explanations. Also because, to contradict me, there is the excellent execution of everything else in the instrument. What do you think?
