7i40h motor size

Hello
I would like to replace the drives of the cnc, with 2 7i40h for 3 motor there are no problems but that of the x axis is larger. 1.75 nm 90 volt 7 amp four brushes dc motor.
of course by feeding it to 70 volts as it is working now.
will it be risky or can it be done?
thank you
Mauro

thanks Andy,
the 7i40h is given for 80 volts 5 amps, continuing to power it at 70 volts I should be quiet I think ... as torque I do not need all that has.
I read that it has all the protections should not burn.