Any brand-new machine that’s introduced by a manufacturer in spite of the recent slump in snowmobile sales is bound to draw attention.
Sno-Jet tears into the ‘75 model year with three new SST’s, redesigned from the snow up. The new SST line offers two free-air models, the SX 440 and SX 340, and one new fan cooler with a twin S-440 engine. In the SNOW GOER Colorado tests, both the free air and fan SST’s, with Sno-Jet/Yamaha engines and transmissions, had even the Yamaha crew shaking their heads in amazement.
First in field speed tests, the fan 440 ate up the competition. With a 63-mph top speed, it was excelled only by the outstanding performance of the Rupp Nitro which topped the class with 66 mph, Later, this SST became the center of attention as it smashed all of the other 12 fan 440’s acceleration records.
It clocked the ½-mile in just 11.3 seconds and the ¼-mile in just 18.4 seconds.
Dynamometer testing also showed the fan SST second to none in most categories. Its top speed on the dyno, both with and without load, topped all other machines in the fan-cooled class. Under a load simulating five inches of powder snow, the sled managed 62.8 mph. Without load, its top speed jumped to 81 mph.
Likewise, its 30 delivered horsepower outclassed all the rest, though the Rupp Nitro came within a ½-hp of matching its strong muscle.
But its dyno recordings weren’t 100 per cent perfect, It faltered somewhat in draw- bar pull, for example, and came in eighth with a pull of 274 lbs. Also, when dyno load was boosted to bring t’he track down to 30 mph under full throttle, its new clutch allowed engine speed loss of 1,400 rpm. This rpm loss before down-shifting was the second greatest loss of the class. Only the Yamaha GP suffered a greater rpm loss, dropping 2,200 rpm before recovering.
Trail riding the fan SST 440 turned up another way Sno-Jet compromised to make this machine a barn burner in straightaway flat running. It was somewhat short on comfort, despite a 6½-inch layered foam seat, compared to other sleds excelling in this respect. Most of this criticism stems from suspension bottoming out for heavy riders, though field adjustments may have circumvented the problem.
At least it should be possible with SnoJet’s new fully adjustable “Multiflex 75” slide suspension. This year the suspension claims less weight, better weight transfer and durability. Its weight has been trimmed using high-strength aluminum slider shoe supports. Free-wheeling 6-inch idler wheels in the rear, plus frontal wheels, help take weight off slider shoes and cut wear on hard pack and ice. Also, track clip guides help cut friction during cornering.
The entire suspension is housed in a new tapered aluminum tunnel designed to give maximum traction either in deep snow or hill climbs. Result is that, with more clearance, running boards have less of a chance to hang up the sled. Sliders run over the Sno-Jet built drive, high profile track. Called Positrack Plus, it’s 15½ inches wide by 115 inches long.
The SST’s 405-lb. wet weight came within a pound of matching the lightest sled in the 440 fan-cooled class, the Scorpion Whip. Light weight, plus a well-tuned Keihin carb feeding its reed valve twin, helped the SST to make a respectable showing in fuel economy tests. With 21.9 mph, its mileage was third best of the 13 fan 440’s tested.
The machine’s advanced front engine design, plus a ski stance widened 4 inches to a total of 30 inches between ski legs helped it rank among the top four fan machines in stability tests. It broke away from the SNOW GOER tip-over platform only after being inclined to 40.5 and 43 degree angles, left and right respectively.
This stability was evident in trail tests. SNOW GOER riders rated the SST superior in both maneuverability and steering. Contributing to its easy handling are shock absorbers mounted over tapered mono-leaf ski springs to forged steel 1-inch diameter ski legs. Skis have carbide runners.
The ‘75 SST has a long list of improved features which a buyer would expect in a new-line machine. Chaincase and Sno-Jet built “Sonic-Tuned” exhaust system are new, as well as a 6 gal, easy access side-fill fuel tank, adjustable padded handlebars, air intake silencer from last year’s free air Thunder-Jet, detachable headlamp and smoke-tinted pop-off windshield. Other standard features include rubber padded engine mounts, 3-way ignition switch, speedometer with trip odometer, tachometer and 8-inch disc brake. Backrest is optional.
Besides this machine and the free air SST’s which deserve a buyer’s serious consideration, Sno-Jet will also be offering the 440cc Whisper Jet, the 295cc Astro Jet and the 340cc Astro SS, along with the competition minded Thunder Jet. But after one look, it’s likely you’ll agree the new SST’s have put this company into an entirely new class of excellence.
Manufacturer: Sno-Jet, Inc., Burlington, Vermont 05401. Suggested Price: NA
Engine: Sno-Jet/Yamaha S-440 reed-valve fan-cooled twin.
Clutch: Yamaha torque sensing.
Carburetor: Keihin diaphragm type.
Dimensions: Height without windshield, 28-in. Width, 35½-in. Length, 101-in.
Track: Sno-Jet “Positrack Plus” 15.5-in. wide reinforced rubber.
Suspension: Multiflex ‘75 double rail slider with aluminum slider shoe supports.
Brake: Mechanical disc.
Fuel Tank: Center-mounted 5,5-gallon capacity.
Weight: 405 lbs. wet; 367.2 lbs. dry.
Location: Rabbit Ears Pass, Colorado.
Test Conditions: 4 ft. base spring snow.
Altitude: 9,426 feet.
Top Speed On Snow, mph: 63.
Acceleration 1/e-mile, sec: 11.3.
Acceleration 1/4-mile, sec: 18.4.
Gasoline Economy, mpg: 21.9.
Overturn Angle Left, degrees: 40.5.
Overturn Angle Right, degrees: 43.0.
Noise, at 50 ft.: 77.0 dbA.
Drawbar Pull On Dyno, pounds: 274.
RPM Loss On Backshift: 1400.