The Duo-Art accordion valves should all be set to a standard valve
travel of 0.032" to 0.035" (35/1000 of an inch).  0.036" is acceptable
as well, but the travel is definitely less than 0.040".  The two valves
in the center (pneumatics #8) could have a wider travel but that is not
necessary because of the small amount of air volume in accordions.

Do make sure the accordions are airtight.  The factory sealed the pouch
leather used on these with egg white.  If the leather is not airtight
but _recent_, you may paint some egg white onto the leather after
beating the egg white slightly before use.  The pouch leather used on
these is open to atmosphere and only lasts about 20-25 years in the
climate we have here.

Any valve travel above 0.040" will be too much.  It will slow down
response and will lose pressure as the valve is in motion.  Use some
paper shims under the top valve facing leather to regulate the travel
down to the correct distance.

Doug L. Bullock
St. Louis Metro, Missouri
http://thepianoworld.com/