SPECS FOR SAITO 120

Type: 4-stroke
Displacement: 1.20 cu in (20.00 cc)
Bore: 1.26 in (32.00 mm)
Stroke: 0.97 in (24.80 mm)
Cylinders: Single - Chrome Plated
Engine (Only) Weight: 28 oz
Crankshaft Threads: M8 x 1.25mm
Benchmark Prop: 15x8 APC @ 9,000
Prop Range: 14x8 - 16x10
RPM Range: 2,000 - 11,000
Fuel: 10%-30% Synthetic
Mounting Dimensions: 138 x 69 x 133 mm
Muffler Type: Cast
HP: 2.2
Cylinder Type: AAC
Carb Type: Barrel, 2 Needle Valve
Crank Type: Ball Bearing

The Saito 120 comes a full 5oz lighter than the O.S 120, and with a much higher output rating of 2.2HP compared to the O.S 120 Surpass with 1.9HP. Again I am not trying to start an arguement, but just wanted to give you something to think about in regards to varying engine weights for your spacewalker, and what kind of power to expect if you decide to try something else in your spacewalker. IMO, I think the Saito 120 would be great in the Spacewalker, but rotational torque of that strong engine may effect handling in several ways. Just more food for thought.