SNOPRO 1974 – Does Racing Improve the Breed?

It’s hard to believe but 43 years ago this past fall the snowmobile world was abuzz with a new race series called SnoPro. We all recognize SnoPro as the name used by Arctic Cat on a number of its sleds, but in reality the label “SnoPro” was proposed by Conrad Bernier who was the race director for Bombardier for the new oval race circuit.

SnoPro was created to allow the factory paid riders to compete against each other with one of a kind (call it F1) race sleds. A huge problem back in the early 70’s was the factory pros with factory mechanics and big budgets were competing against the independent weekend warriors. In most cases the winners were the factory pros. SnoPro was created to eliminate that problem.

SnoPro was to be F1 on snow with limited restrictions on sled dimensions. There were basic rules under which the sleds weight (250 lb. minimum) and dimensions were defined. All sleds had to be track driven, ski-steered. Gasoline was the only fuel allowed, as alcohol burning engines were banned. Superchargers and turbos were not allowed. Three engine classes (340, 440 & 650cc) were contested at each race.

These rules were all agreed to by the manufacturers in the spring of 1973 and they all went off to their respective facilities to build the future of snowmobiling with a deadline of Sunday December 9, 1973 in Ironwood Michigan, the first race.

Prior to SnoPro, modified race sleds built strictly for the race track (no lights, full mod engines) were available to qualified racers, much like today’s snocross race specials. The ‘74 season would see the end of full mod race sleds. Factory race departments were now building in some cases two or three sleds per class. Only Polaris and Arctic would field more than two drivers.

While excitement was building across the snowbelt for the season to begin, North America was to about to get a reality check on Mideast oil dependency with an oil embargo. All of a sudden, gasoline rationing and long lineups at service stations were front-page news. Power sports were seen as a frivolous activity that wasted valuable fuel.

Burning fuel out trail riding or, even worse, going racing, was seen as completely irresponsible. The snowmobile companies had to go into damage control. Why? Survival. Inventory of unsold sleds was sitting at 315,000 going into the spring of ‘73. This huge volume combined with interest rates @12% was all it took for Ski-Doo to pull out of the SnoPro circuit and divert funding to dealer programs to instruct consumers on how to drive their snowmobiles to use less fuel.

Ski-Doo pulling out of SnoPro was a huge blow to the new program (think Ferrari pulling out of F1) yet the other sled builders decided the show must go on.

History shows that the sleds raced that winter were for the most part conventional in design except for the twin track Alouette sled. Snowmobile manufacturers were now in the infancy of liquid cooled engine applications. Clutching continued to evolve as well as track suspensions built specifically for the oval track. New body styles, seat designs and even the leaf spring ski were evolving to improve cornering.

The final stats at the end of the race season reveal that Polaris claimed the 340 and 650 title and Yamaha the 440 classes. Why the results ended the way they did is as much about where the present status of snowmobile design was back in ‘74 as where the future of snowmobiling was headed. What follows is a recap of the SnoPro sleds from Arctic Cat, Polaris, Ski-Doo and Yamaha and the models that later evolved from them.

1974 Arctic Cat Sno Pro
The Arctic Cat race sled featured the first Kawasaki liquid cooled engines. Liquid cooling would reduce engine noise and provide more consistent power. The sled was only 23 inches high, 100 inches long and built around a 34 inch ski stance. Compare that to the 2014 ElTigre @ 48 inches high, 125 inches long, with a ski stance of 42 inches.

Arctic Cat struggled in ‘74, as the sled was heavy and slow off the line, but by the end of the season they were back in the winners circle.

1974 Arctic Cat Sno Pro

1976 Arctic Cat Z
The 1976 Z did not arrive with the Kawasaki liquid cooled (LQ) engine from the ‘74 SnoPro. It did come with a 250 LQ Kohler engine or the new 440 Suzuki LQ engine, which was the first Arctic Cat-designed LQ engine for a stock racer. Styling was right off the ‘74 SnoPro, but excessive weight would be an issue limiting success on the race track in stock racing

1976 Arctic Cat Z

1974 Polaris Sno Pro Racer
The Polaris race sleds continued to use the free-air Fuji engines with larger cooling fins. Polaris clutching was still at the top of the game and most efficient at transferring power to the track. Body styling was a glimpse into the future.

1974 Polaris Sno Pro Racer

Polaris actually labeled these sleds as 1974 Starfires, but more commonly have just referred to them as the ‘74 Sno Pros. Only 9 were built, with an all magnesium tunnel, bulkhead, 4-band track that is super thin, titanium cleats, lightened ‘73 Starfire suspensions, aluminum skis, leaf springs made in France, all titanium shafts, titanium clutch guard, titanium exhaust flanges, aluminum pipes…. nothing but the best at the time!

1976 Polaris TX Starfire
The ‘76 Polaris TX was strongly based on the ‘74 SnoPro. The same free air motors built by Fuji were available in 250, 340 and 440cc sizes. Features included fiberglass belly pans, aluminum slide rail suspensions and a jackshaft mounted secondary. All were proven on the ‘74 race sleds. All that was missing was liberal use of magnesium to reduce sled weight.

1976 Polaris TX Starfire

1974 Ski-Doo Blizzard
Ski-Doo never actually raced this sled but Bombardier continued to use Rotax free-air engines. The rotary valve intake engines were to be used in the 340 and 440 motors. The sleds were built around a 38-inch ski stance. The sled, like Polaris and Yamaha, incorporated aluminum, magnesium and titanium alloys for lightweight strength. Carbon fiber had not yet made its way to the world of race sleds. Polaris clutches were to be used. Carburetion that would adjust to changes in barometric pressure was under development. Each sled was tailor made to fit Yvon Duhamel and Mike Trapp.

1974 Ski-Doo Blizzard

1975 Ski-Doo T’NT RV
The 1975 Ski-Doo RV chassis was similar to the ‘74 SnoPro with the exception of not using a jackshaft mounted secondary clutch. The RV came with a 245cc rotary valve engine, Mikuni slide valve carbs (which replaced Tillotson carbs) and a cleated track. This sled dominated the 250cc class in 1975.

1975 Ski-Doo T’NT RV

1974 Yamaha SRX 440
Yamaha chose to only compete in the 440 cc class. This was Yamaha’s first liquid cooled engine in a snowmobile and, unlike Arctic Cat, they built a chassis right at the 250 lb. minimum allowed. This sled featured magnesium engine components and Ackerman steering located beneath the belly pan to lower the engine mounting. This was without a question the most expensive race sled with only 3 built. The 440 class was the perfect motor for LQ in the mid 70’s. The extra weight was offset by the hp of the motor.

1974 Yamaha SRX 440

1976 Yamaha SRX
The liquid cooled Yamaha engines would appear in the 1976 SRX stock racers. The chassis was a hybrid between the ‘74 SnoPro SRX and 1975 GPX free-air racer. The expensive metals used in the engine and chassis were replaced with aluminum. This was the only sled that would compete with the ‘76 Mercury Snow Twisters. This body style was a unique Yamaha as was the rear suspension. Yamaha had the most success with liquid cooling in the mid 70’s prior to the Kohler liquid cooled engine in ‘76.

1976 Yamaha SRX

Summary
The ‘74 SnoPro season saw the tried and true free air powered Polaris sleds with exceptional clutching and light weight chassis dominate the lower hp, 340 class where the extra weight and complexity of an LQ motor was a detriment. The big 650 cc class was also dominated by the mega finned triple free air motors from Polaris. Only Arctic Cat built a LQ triple but the extra weight proved to be the Achilles heel of these sleds. Arctic would abandon the LQ motors in ‘75 in favor of a free air motor to reduce weight.

The 440 class was perfectly suited for a light weight LQ engine in low weight chassis. The 440 class was dominated by Yamaha and later Arctic Cat. The challenges facing the industry in the mid 70’s were excessive noise and more engine failures as free air engines reached their max hp for the cooling available with enclosed hoods to reduce noise. In retrospect the 440 class was the most relevant for the consumer snowmobiler and the free air motor of Polaris was a good 2nd/3rd place engine.

Change was coming fast in the sport and LQ was the future. SnoPro may have only lasted for a short time but the outcome from 40 years ago is still in place today on the two stroke LQ engines that power the 2014 sleds yet today.

Story by Hal Armstrong
Follow Hal in SnowTech Magazine, or @sledtimemachines on Facebook.

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