Noisy Yamaha action

[David Love]

List:

I'm working on a Yamaha C5 c1979. I just replaced the hammers and shanks.  
Piano sounds great.  But, the action is very noisy.  Two types of noises 
seem to be there:  First, there is a sort of click that one frequently hears 
when a note played or even tapped.  Interestingly, the noise does not occur 
if you keep playing the note, only on the first blow.  In a discussion with 
another tech, he informed me that some Yamaha keys tend to leach sap onto 
the balance rail pin creating a sticky residue that (when the pin is too 
tight) makes a noise (clicking type) when the key is first played.  The 
noise does not continue with repeated blows because the contact has, in 
effect, been broken.  Once the key rests for a bit, this contact sets up 
again and the noise will again be heard when the key is next played.  Some 
of the balance rail pins are, in fact, a bit tight.  I have not heard this 
theory before and would be interested in some comments if there are those 
who have.  I can certainly ease at the balance rail, but if this noise is in 
part because of some sort of residue, what can the pins or key be lubricated 
with that will have a positive effect.  I normally lubricate the pins with 
McClube (and these pins have been lubricated), so I suppose my question is 
what would you lubricate the balance rail hole in the key with.

Second, there is a fair amount of side to side play in the whippen flange 
and I when I push the repetition spring from the side it makes a slight 
click where it enters the back of the jack tender.  Aside from addressing 
the problem at the balance rail, my first thought was to repin the whippen 
flanges and lubricate the lower part of the rep spring with some Protek 
grease type lubricant.  My second thought was to replace the whippens.

Note:  The problem is not loose weights either in the key or the damper 
flanges (noise continues even with dampers lifted out of the way).    
Backrail cloth and cloth on the heel of the whippen are fine.  Leather on 
the balancier is not hard.  Hammer flanges are fine, and the hammer/shank 
glue joint is solid.

P.S.  Though the action is somewhat "rattly", I realize that actions do make 
some noise and that eliminating all of it is difficult if not impossible.  
Nevertheless, this customer is sensitive to extraneous action noise and I 
would like to get it as quiet as possible.

I appreciate your comments.

David Love


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