Disklavier

Hi everyone, here's my problem :
I am triggering the piano from within a PC with Cubase, i am sending 
very little information at a time for example if i send only 1 Note 
On (and velocity) and a sustain pedal down message (c64 127(i've 
tried lower values like 95 to no avail)), the sustain pedal will 
randomly start clanking very fast (i'm french for lack of a better 
word the analogy would be it sounds like someone that hits their 
teeth very fast), sometimes it does it sometimes it doesnt you can 
hear the mechanical part sound when it's working right it's like a 
humm but as soon as the clanking begins you can't hear the sustain 
pedal mechanics anymore, if i look in the piano i can see the whole 
section that goes down when a sustain pedal goes down going up and 
down at a very high rate of speed about 2 times per second, it does 
it gently but still loud enough so that you can hear it.

I've tried different midi configurations with same results, i'm 
thinking this is mechanical and either part of or the motor 
controlling the pedal is damaged or there's a problem with the 
disklavier controler.

Anyone ever get this problem, is there a special midi trick to this 
or is this purely mechanical ?

also, is there any way around the 16 second note length lock on the 
piano ? i'd reall like to be able to get 20 seconds....

Thx guys
Franky.