The Compumotor integrated gearmotors are obsolete and no longer available. For replacements, the Stealth Gen II PS90 servo class gearbox is a very close replacement.
Note that the motors and gearheads are purchased as separate items:
1. N0923HR-NGSN......Servo Motor
2. PS90-010-L2..............Inline PS90 Stealth Gen II gearhead, 10:1 ratio low backlash
2. MU90-001.................Mounting kit
The MU90-001 is the mounting kit to fit the N092 and J092 motors to the Stealth Gen II 90mm gearheads.
The G08 was a 8:1 ratio. The Stealth has as standard 7:1 and 10:1 (exact ratios). An 8:1 ratio has been done and is available as a custom.
The G12 was a 12:1 and G16 was a 16:1. The Stealth has as standard 3:1 and 4:1 ratios and these can be used for these same ratios as a custom.
Shorter shafts to match the previous gearmotor and/or the Woodruff key are also available as custom.
The above is summarized based on catalog specifications. However, application requirements may be different; the PV90 value line gearhead could also be considered.
As reference for Compumotor Gearmotor catalog specs:
The integrated gearmotors have the pinion machined into the motor shaft and thus cannot be disassembled and the motor re-used with the new gearheads.