IMHO the sound range of instruments wether implemented in keyboards (YamahaSounds) or provided by midicontrolled hard-/software is always limited to a practical/natural range or the range of the original instruments the samples were taken of.
PSE find here a table, were the limits as described in the GM Midi Convention are listed. There You will find also the limits of the Accordion.
http://www.jososoft.dk/yamaha/articles/midi_8.htmThe range of my Hauptwerk church organ samples is strictly limited to the range of the original manuals/pedal.
The range of theatre organ samples depends on the specific range of the ranks. PSE see
http://www.toff.org.uk/relay/extensionandunif.htmlIn Hauptwerk Organ Settings the range of the incoming midi data can be transposed by semitones or octaves.
Yamaha Tyros 4 as a upper class keyboard should also provide a similar means for its output.
AFAIK the Yamaha Key can display the midi output. Another means is to view the output is MidiOx, which can be downloaded for free.
Amun