The motor can be purchased separately or combined with a double reduction gearboxes. The latter units give slightly better control. Gearboxes may also be purchased separately. Flywheels for these units, which are optional extra, are available in two sizes – 22.0 mm or 28.5 mm diameter. The flat sided JH motor is no longer available.

The double reduction gearbox with this motor is available in two ratios; 25:1 & 33:1 – the lower the number the faster the drive axle revolves. JH double reduction units are also available with 1/4” axle for Gauge 1.

The JH motor on the double reduction gearboxes has a 2.3mm shaft, a no load speed of 8,200 rpm (+/- 10%), and a stalled torque 409 gram cm.