Snow Goer’s Wyoming Tests (1973 Snowmobiles)

It had all the atmosphere of a carnival just coming to town. Thursday, April 6, 1972, was the opening day, and as the sun rose over the horizon to light up fresh Wyoming spring snow on the sides of the Grand Teton mountains, SNOW GOER was ready for the 73’s. The dyno was set up, and both the tip-over platform and decibel meter were working and waiting. Letters and telegrams had confirmed the arrival of new machines from at least 26 major companies across North America. Togwotee Mountain Lodge, 40 miles north of Jackson Hole, was filled to the brim with snow’ people, including a SNOW GOER staff of eight.

Snowmobile manufacturers trucked, trailered and flew next season’s machines more than 35,000 miles to be there. And the next 10 days, for the SNOW GOER evaluation team, were to be filled with expectation, excitement, surprises, satisfaction, and even some disappointments. But as the SNOW GOER crew rode these snowmobiles, a half a year before their time, each member of the staff was impressed in total by the giant steps forward taken by the industry in just the past short year. The sport of snowmobiling is alive and well, and if SNOW GOER’s April tests proved one thing, it was that a majority of snowmobile manufacturers have put a load of time and talent into improving details on their machines to make snowmobiling during the 1972/73 season more enjoyable than ever before.

You know how when you ride a relatively fine snowmobile and a little thing like a bad throttle control starts bugging you, and pretty soon your mind rushes past the terrific ride, super power and light touch steering and all you can think about the whole afternoon is that damn throttle? Those are the things many companies are hitting hard in their ‘73 offerings. Depending on which machines you look at, reserve judgment until you hear what’s happening in overall refinements that give a rider a total machine.

Also, remember a couple of years ago when you had to look, hard and long to come up with a snowmobile engineer who would agree that snowmobiles could be quieter? Snowmobile c o m p a n i e s have waged a full-scale war against noise and the Wyoming tests were a mass R & D department demonstration on how to cut out the snap, crackle and pop of two-cycle snow travel. Each company has fought its Own battle with an incredible array of devices dreamed up by sound engineers. But as predicted, it’s true you don’t get something for nothing. The SNOW GOER team noticed a definite loss of power on some models, sacrificed for the quiet. But we’re sure when you ride a ‘73, both you and your big-eared neighbor will agree the advantages are well worth it.

Okay, you say, knock off all the hogwash and tell us which one is the best machine on the market! We thought you’d ask that question, so one day after we got back from Wyoming, we had a meeting of staff test riders, and started our eliminations. From the 26 machines in our tests, we easily narrowed these 26 down to 10 in the Grand Prize—Best Machine Sweepstakes. Then, after some deliberation, we cut out another five candidates for the Best Snowmobile without any major fist fights. But in trying to get closer than five, the meeting broke up amidst an exchange of four-letter words, with each rider unwilling to compromise his favorite machine.

So then, to resemble some sort of corporate dignity (the president’s office is right next to the conference room and if he heard somebody busting up the paneling, he might put us all down in The Bindery) we closed the meeting abruptly and put our list of top five in the vault, not to be opened until next year. The only reason we’re even telling you all this is to show you that there are a number of excellent sleds in the offing, and to point out the fact that the best machine to buy depends at least 50% on the individual buyer’s tastes.

But to help you get a better idea this year of the 73’s performance characteristics, we’ve added a comprehensive dyno report, sound tests at operator ear level at 3A-top rpm plus stability figures from a tip- over platform, to our general summaries of individual riding tests. The dynamometer was supplied to SNOW GOER for the Wyoming tests by essentially the only company which makes a transportable model especially for snowmobiles, Hartzell Corporation of St. Paul, Minn. Hartzell even sent their top dyno man, Russ West- berg, to make sure the Mark II was run right and impartially.

Probably the most interesting fact about snowmobile dyno tests is that even the best snowmobile on the market today is only about 35% efficient in delivering rated horsepower to its track. This means that even the best snowmobiles today lose 65% of rated engine horsepower through the power train, and that if your snowmobile’s engine is rated at 20 horsepower, the most you could possibly expect to reach the ground would be 7 horses. This compares to only about 30% rated horsepower loss in motorcycles; i.e., 20-hp cycle would probably deliver about 14 horsepower to the rear wheel.

The Snow Goer crew checks the readings on the Hartzell Mark II Dynamometer.
Accuracy of the Hartzell Mark II dyno is pegged at plus or minus 2%. The track of a snowmobile running on the dyno turns 16 pneumatic tires which form the test bed. The wheels drive a chain gear unit, which in turn drives a hydraulic pump with a hydraulic reservoir. Turning down a regulating knob restricts the hydraulic oil flow. Load is measured in pounds per sq. in. (psi) on a gauge on the side of the test bed. Another gauge on the test bed measures mph.

From mph readings at various loads, a delivered track hp curve can be developed (see illustration). The power curve charts you see in this issue are stylized versions of a form developed by Hartzell to chart a power curve from readings at nine psi loads on the dyno which roughly correspond to snowmobile operation under various types of snow conditions. The six psi loads SNOW GOER used in Wyoming roughly w e r e equivalent as follows: 250/psi—ideal hard pack; 500/psi—compact snow trails; 750/psi—breaking trails in light snow; 1000/psi—braking trails in powder or wet snow, and 1250/psi—breaking trail and climbing. Besides the psi and mph gauges on the dyno’s test bed, Hartzell has an additional instrument package that sets on the side of the test bed and contains cylinder head and exhaust gas temp gauges, tachometer and Bosch ignition tester. The curve of actual horsepower delivered to the track is a function of mph and psi. The only instrument used on the instrument head in Wyoming was the tachometer w h i c h unfortunately did not accommodate engines with CDI ignition (Hartzell does have instrument packages which have a tach set up for CDI) so we were unable to check tach error on a number of machines.

In our Wyoming dyno tests, we found a critical factor in getting accurate track horsepower readings was to have adequate lubrication on slide rail machines with either snow or a water-detergent combination. Whenever slide rails got hot or sticky, horsepower dropped dramatically. Of the 26 ‘73 models, only one was not tested on the dyno; the Raider, with 35 inches between its two 8-inch wide track. It simply would not fit on the dyno’s test bed.

The tip-over platform used was trailered to Wyoming by Leisure Vehicles (makers of the Raider) from Troy, Michigan. As the photo shows, it simply is a swinging platform with a degree indicator on a protractor-like dial on one end. Throughout the tests, the SNOW GOER crew experimented with the tip-over platform. During the first few days, test snowmobiles were placed on the platform, and the rear end allowed to slide to the downhill side as the platform was swung out to test stability.

Checks with blocks of wood holding the rear-end in a straight-line axis with the platform showed little difference in degree readings.

The tip-over platform, furnished by Leisure Vehicles, gave relative comparison of stability among '73 models in Snow Goer tests.
Leisure Industries also supplied a regulation decibel meter for noise readings. Some company reps were skeptical of our bypassing the J-192 SAE noise standard for snowmobiles which requires decibels read at 50 feet from the machine, at full rpm, with the machine running perpendicular to the meter on three inches of grass. The J.. 192 standard is how the ‘73’s are tested to see if they conform to the standard of 82 db(A) level which has become law in many snowbelt states. We tested noise at the operator’s ear level on the dyno at three-quarter top rpm. The purpose of our noise tests was not to determine which machines did or did not conform to the 82 db(A) limit, but rather to serve as a comparison between the new models. We know that our db(A) readings also included noise from the Hartzell dyno, and we felt taking all readings at three-quarter rpm would still be much higher than what the operator would experience in normal operation. The important criterion of any test, of course, is standardization.

In case you’re not aware of how the decibel scale works, you should know that it’s logarithmic, not linear, in progression. What this means is that a decrease of six decibels on the A scale, say from 88 db(A) to 82 db(A), actually cuts the sound level in half, or vice versa. Our ear- level, ¾-rpm tests on the dyno showed a difference of 19 decibels on the A scale on ‘73 models, ranging from the lowest at 93 up to 112 db(A). In riding tests, our crew could actually notice the difference on their ears in machines which varied by as little as three decibels, and we can say there is one hell of a big difference on the ears between 93 db(A) and 99 db(A).

As you can expect, machines arrived at Togwotee Mountain Lodge in a whole variety of conditions. Some were finely polished, carbs finely tuned for the altitude, suspension and steering set up precisely for the snow conditions, and even for the weight of various test riders, Others were found to be only roughly tuned for conditions, and chances are, with just a little work, performance on these sleds could have been increased by between 5 and 10 mph top speed on the dyno. Of those few ‘73 models that were grabbed out of the crate and set up in a couple of hours, we’re sure they could have turned out 15, or even 20 more miles per hour at top speed.

As a final word, we would like to caution the buyer, when looking at ‘73 snowmobiles, against super low price good deals. As the snowmobile industry progresses, a few companies find themselves facing the fact that they cannot keep up with technological advances required to remain competitive, and still penetrate enough of the market to make money. In some cases, companies who have decided in closed meetings to pull out of the market may still have a sizeable inventory in the warehouse. This means they will try to move out this inventory, sometimes at bargain prices, and probably let the public know they’re out of business the next year.

And when talking prices, keep in mind who you’re talking to. We can show you stacks of testimonials from disgruntled snowmobilers who wished they would have bought their machine from a reliable dealer rather than buying on price alone. Remember that the bargain snowmobile may not turn out to be the bargain you thought it was, after all. Forewarned is forearmed.


The Test Crew: It’s hardly an industry secret that SNOW GOER staffers are involved more than personnel of any other publication in the sport of snowmobiling. Collectively this crew rides more brands of snowmobiles more hours than 99% of all enthusiasts across the snowbelt. Each• season, while enjoying snowmobiling wherever the snow falls, from Switzerland to Alaska, these staffers also experience their fair share of snowmobiling problems. They get to know what problems various machines and conditions can present; which are critical and which are not.

At home in Minnesota, this crew has a strong sampling of brand new machines at its disposal each season. Last winter, for example, the SNOW GOER staff put new machines from 14 major companies through their paces in about every imaginable snow condition, racking up more miles on different brands than even the R&D departments at the biggest factories. This riding experience proves most valuable each spring when SNOW GOER takes a look at what snowmobile manufacturers are offering the buying public for the following snow season.

While you won’t find either a racer or an engineer on the staff, you will find a big bundle of snowmobiling experience which forms a solid basis on which to build on by conferring with snowmobile engineers, or by observing machine performance on the race track or in rough country. Members of the staff obviously vary in shape, size and personal tastes, and this further broadens the SNOW GOER composite of snowmobiling experience.

This total experience is why we feel the reports on the following pages are more firmly grounded than many other snowmobile evaluations, some of which often rely on the opinions of only one or two riders. SNOW GOER’s group approach helps keep reports on new models as objective as possible by offering the best thinking of a cross-section of active, experienced riders. When three of four SNOW GOER riders all comment either positively or negatively on a particular feature in new model tests, we know we’re “right on.” On the other hand, if riders come up with contradictory reports, then we know that we’re in an area of personal like or dislike, and we raise a skeptical eyebrow and check the facts out further.

The end goal is, of course, to let you know as accurately as possible what the sport of snowmobiling holds in store for you next season.

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