The YC-25D is basically a dual-manual version of theYC-20 with several added features. The upper keyboard has 49 keys, and the lower manual has 30 Treble keys and 19 Bass keys which can be switched to extend the Treble section. Instead of having a Ch I and Ch II set of levers, one set is exclusively for each manual. Unlike the YC-20, both the upper and lower levers produce the same flute-like tone as the II section on the YC-20  However, the lower manual has a nice key-click, similar to the one found on the YC-20/YC-30 section I voices. The upper manual has all the same footages as the I section on the YC-20, and the lower manual has the same footages as the II section, plus a 2-2/3' lever. Both sections have the bright lever as well. Since the cheesier sounds of the YC-20's I section are gone, the upper manual of the YC-25D has four additional voices: Trombone 16', Kinura 16', Trumpet 8', and String 4'. These provide a nice selection of fuzzy, gritty, cheesy combo organ sounds.

The Percussion section has been enhanced, with separately adjustable 4' and 2-2/3' levers, comparable to 2nd and 3rd harmonic percussion on a Hammond. There's also a Length lever for the percussion, which increases the time it takes for the percussion sound to die down. Similar to the Short/Long switch on a Hammond, but continuously variable. Percussion as well as Touch Vibrato are available on the upper manual only. The upper manual has a couple of additional features. There are two tabs to the left that select Touch Mute and Attack Glide. Touch Mute reduces the volume and mellows the timbre, but moving the keys side-to-side causes the timber to waver, giving sort of a "wah-wah" effect. Attack Glide is similar to Farfisa's Syntheslalom. When you press a key, it quickly "glides" up to the desired note. There's also a lever to the left of the upper manual that controls the volume balance between the two manuals. The lower manual is basically the same as the YC-20 with the II section only, except it has the additional 2-2/3' lever. The Bass section is monophonic (when using the Bass voices - polyphonic when playing the treble voices), but adds a couple of extra features. The other feature appears to vary on different models. Some have a "Sustain" lever, that adds a sustain after key release. This is the feature specified in the 1974 and '76 sales brochures that the picture below comes from.

In full working condition. Comes with Foot pedal that is semi functioning.