I meant that any type of 4000 series like 1n40002Hi,
Please give a link to the datasheet of "Universal diode". ;-)
Generally it is no good idea to run an inductive device (motor, valve, transformer...) that is designed for pure AC on DC (or AC + DC). Otherwise the magnets (inductor core) gets saturated and causes high current, and high dissipated power (heat).
A better solution could be to use two anti series connected Zeners to reduce both half waves symmetrically. Mind the dissipated heat. For sure a resistor in series could work, too, but with less motor torque...
Often used: Triac phase control. (Dimmer).