<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; = charset=iso-8859-1"> <META content="MSHTML 6.00.2900.2769" name=GENERATOR></HEAD> <BODY> <DIV><SPAN class=312035601-02112005><FONT face="Comic Sans MS" = size=2>Good evening,</FONT></SPAN></DIV> <DIV><SPAN class=312035601-02112005><FONT face="Comic Sans MS" size=2></FONT></SPAN> </DIV> <DIV><SPAN class=312035601-02112005><FONT face="Comic Sans MS" = size=2>I had two tuning jobs yesterday that involved relatively new Yamaha verticals - an = M500 and an M450.  Both have very jumpy jacks (or, at least, that's my = analysis of why they're tending to double-strike, even when well-regulated), and = I'm wondering why.  </FONT></SPAN></DIV> <DIV><SPAN class=312035601-02112005><FONT face="Comic Sans MS" size=2></FONT></SPAN> </DIV> <DIV><SPAN class=312035601-02112005><FONT face="Comic Sans MS" = size=2>Both have plastic jacks and synthetic buckskin.  The M500 had been treated = with something that looked graphite-like and was less jumpy than the = M450, which leads me to believe that the proper lubricant (or other treatment) might = solve the problem.  I would very much appreciate any suggestions as to = how to proceed.  Thanks!</FONT></SPAN></DIV> <DIV><SPAN class=312035601-02112005><FONT face="Comic Sans MS" size=2></FONT></SPAN> </DIV> <DIV><SPAN class=312035601-02112005><FONT face="Comic Sans MS" = size=2>Annie Grieshop</FONT></SPAN></DIV> <DIV><SPAN class=312035601-02112005><FONT face="Comic Sans MS" = size=2>in the wilds of balmy Ioway, where winter is still in our future.....</FONT></SPAN></DIV></BODY></HTML>