Jim Adema

Reflections of Jim Adema magazine article: Page 1 Page 2 Page 3
In Memoriam - Jim Adema
Jim's profile at the Snowmobile Hall of Fame

The latest information/pictures are at the top. The next five pictures were donated by Bob Mackin. A few words on Jim from Bob: I was a close personal friend of Jim Adema and have many unpublished photos of Jim and ThunderJet Racing and Development. In Adema's first race on the 72, he lapped everyone once, but actually could have lapped everyone twice. He let up on the throttle towards the end. His 440 Thunder Jet was dynoed at 60hp, where the factory ski-doo 440 was dynoed at 80hp. Aparently after the race, the skidoo guys were saying they could have caught up to Jim with more HP, they didn't realize how underpowered his sled was already compared to their sleds.

Another one of Jim's projects, he had actually taken a 440 Yamaha, and turned it into a triple by mounting another 440 cylinder. It was completely home made, and he badly beat the factory yamaha team with their 650.

When Jim went to work for Yamaha, he wanted to put a Thunder Jet chassis under his Yamaha cowl and seat but Yamaha wouldn't let him. Wasting Jim's talents as just a driver was the worst thing Yamaha ever did. They lost the greatest talent ever to race a snowmobile. The first time the rest of the industry ever saw the 72 Thunder Jet was at Peterborough. In that race the incredible Adema lapped second place in a 5 lap race!! All against factory machines. I doubt if lapping the entire field in a feature had ever been done before. Jim did it more than once! He was truly amazing.

After Jims tragic death, building faster and faster machines lost some of the fun it had been for me. Jim may or may not have been the best driver but he was without a doubt the smartest setup man.

Jim does sort of have a legendary status, he completely took on the big factory teams by surprise and always kept them on their toes. Looking at the photo ont he left, it only solidifies his reputation, he was just a normal guy. Here is a really rare shot of Jim testing his 71 Thunder Jet in Grand Mesa Colorado. If you look closely at the photo on the right, you'll see two spindle mounts on each side of the front bulkhead. It was used for testing different ski stances.

This is Jim's 1970 GT3 (800 hirth). He was racing this prior to getting involved with the Thunder Jets. If you look really closely, it looks as though it was actually a GT2 to start, then Jim added his own 793 Hirth and jackshaft.

A legendary photo!

Jim's homemade triple mentioned above? Just recently, photos of the engine surfaced in the book True Blue: Remembering Jim Adema, by Tom Van Dyken. Even more recently, the two shots below surfaced showing the engine in a 71 Thunder Jet. The first photo was taken by Richard Klein. Here's the story from Richard:

When I was about 16 in 1971 I was fascinated by the 3 cylinder sleds, and while attending a race at Hidden Hollow Golf Course near Saginaw Michigan, I took the photo below of Jim's Sno-Jet noting on the 35 mm slide card that the sled won the main event. I had no idea who Jim was but knew that Yamaha did not make that thing and it must have been hand made. I was impressed and never forgot it. After recently reading True Blue, I became interested in who the person in the slide was and shared the slide with my friend John. We projected it on his screen and took a digital picture of it for sharing, but still do not know who that is. Unfortunately, that was the only picture I took of that sled back then, but another exists which can be seen below (second photo). I've always relished this photo of our late, great Phil Mickelson from his book The SkiDoo Buyers Guide. Not because of Phils 797 Blizzard, but because of the sled next to it which undoubtedly is Jim's triple that I had taken the photo of so many years before. True Blue states that very few pictures of Jim racing the triple exist and although we cannot see Jim in this picture, he's probably behind the bars.

Note that this picture may render upside down depending on your browser/device.

Some of the information below was borrowed from various articles and books over the years.
(Some of the images below are in thumbnail format, so please click on them for the full screen version)

In Michigan, a young husband and wife team raced Sno*Jets for Watercraft Sales Center.  Jim Adema was on his way to the Michigan International Snowmobile Association's Class BB points title with nine victories and nice second place finishes during the season. His wife, Pat Adema was cleaning up in the Powder Puff Classes as well.

In the mountains of Colorado, as soon as the season was over, Sno*Jet engineer Duane Aho and the shrewd young racer from Michigan, Jim Adema, were testing a new concept.Aho had found out what he wanted to know about his first ThunderJet. It was too heavy.It was unstable.It didn’t handle. The new ThunderJet prototype was quite a bit different.

Jim was a brilliant man.  He and Duane designed the Thunder Jet, and did a terrific job. It was low, wide, sleek and very quick. Gave the big factory teams real trouble. The limited edition modified racing machines would be available in four Yamaha "R" type engine sizes. Aho was anxious for the snow. Jim was in no hurry. He was ready to test his Sno*Jet fleet on the grass. Jim was well experienced with motors.

"In the late 1950's, Sam Adema, a Belmont Michigan, man bought an old washing machine engine at an auction. He took it home and gave it to his son, who built a go-kart for his new motor. Young Jim Adema wasn't happy, however. The go-kart was too slow. In just a few days, he had removed it was in the workshop with a sander, trying to shave the cylinder head to make the engine faster. A few years later, Jim and a friend built a go-kart with a Corvette engine that hit 137 miles per hour in the quarter-mile."

Below you will two pictures of Jim's homemade Liquid Cooled 292cc Yamaha Engine. He modified the F/A 292 R type engine, by adding a water jacket. (click on pictures for larger version)


1972, Peterborough, Ontario generated news that echoed throughout the world of snowmobile racing. No one was paying much attention to the low-profile blue machines Jim Adema unloaded in the pits. The quiet young man from Michigan, wearing a bulky blue parka, got the sport’s attention right away. Adema and his ThunderJets were devastating at Peterborough.

The first surprise was his unusual techniques on the track. Adema’s machines hugged the inside rail, even through the corners, while the rest of his competitors rode high and wild around the top fringe of the banked turns.Saturday, Adema won Ontario’s Modified C class, beating Polaris’ Bob Eastman. Ski-Doo won MOD A and MOD D, Arctic won MOD B, and Polaris won the open class.

Sunday, as the temperatures rose and the track turned to slush, Adema stole the crowd’s heart. It started with Arctic winning MOD B again, then Adema took over. He won MOD A, MOD C and MOD D. He was surprised when he discovered Sunday night he hadn’t won the Kawartha Cup. With the scoring system used in Peterborough, the larger modified classes were worth more points.

Adema came right back out on Monday, however, and turned his tricks on the factories again. He won Mondays MOD A and C titles, and rolled up enough points to win the Canadian World Cup. He gave the big factory teams something new to worry about as they left town, and drove toward Wisconsin.

Jim Adema wasn’t gloating over his performance at Peterborough, but he knew he had a decent shot at Eagle River, too. Eagle River’s firm, ice-based track was also suited to his equipment. He didn’t care too much for the snow tracks,  but he loved the ice.

He was still a bit star struck when he drove his inconspicuous trailer full of ThunderJets into the circus atmosphere of Eagle River. Peterborough was the first big race he’d entered. The only reason he went up there was because Sno*Jet asked him to go. Jim had been perfectly content racing in Michigan, where he did very well. The Peterborough experience gave him a different viewpoint.

It wasn’t easy to find Adema among the hundreds of semi-trailers, school buses, pickup trucks and trailers jammed into the Eagle River pits. But the rest of the manufacturers scouted around and found him. They wanted to get a good look at the wide, sleek blue racers.  Adema had an answer to turning corners. He was holding the inside rail even better than Mike Trapp’s Yamaha had done the year before.

Jim Adema launched the Sno*Jet show, winning 250cc class handily. Then fellow Sno*Jet driver Lewis Buerman of Alexandria, Minnesota, beat Skiroules Gilles Villeneuve in the 340 class. Then Adema came out to win the 440cc class. Then young Kim Elmer and his ThunderJet won the 650cc class. Then Ski-Doo managed to take the 800cc class.

Kawartha Cup 1973, Jim Adema, from Michigan, put the pressure on. The Sno*Jet Thunder Jet jockey returned to the scene of his biggest triumph ever, this time with a much improved chance of winning the cup. He had won five classes the year before only to finish fourth in a complicated points system. This time, the system had changed.

Adema, the hood on his blue parka flying, won the 440 and 800cc classes on Saturday, though he wasn’t in the lead. On Monday, it was the 800cc class that would decide the champion. Adema won the Kawartha Cup. Runner up was Scott Hemming, a brilliant Stock Driver from Peterborough.

Sno Pro was added to the Kawartha Cup program. For the first time in its 11 year history, Jim Adema of Belmont, Michigan, successfully defended the Kawartha Cup title. Adema out classed a field of more than 1300 entries to win the Cup. He finished almost 80 points higher than runner up Jacques Villeneuve, a factory backed Alouette drive. And to accentuate the Sno*Jet power, Jim’s tiny wife Pat won the Molson Women’s cup. Peterborough’s Scott Hemming successfully defended his high point stock title.

January 20th, 1974, at the World’s Championship in Eagle River, Wisconsin, after winning MOD 0 and third in MOD I, Jim Adema’s sled broke down. He won a battle with Jacques Villeneuve in MOD IV, but the battle between the two took both out of MOD III and made Dave Corbett of Winnipeg, Manitoba a winner (Dave was also racing a Thunderjet). Villeneuve put a ski in Adema’s track.

Ironwood, Michigan, December 13th and 14th 1975, Jim Adema was driving a Yamaha for the first time in his career, beat Mercury’s Doug Hayes in the 440cc class. Adema was following fellow Yamaha driver Dick Trickle down the backstretch. The time was approximately 4:30 p.m., according to eye witnesses. Heavy, wet snow was falling.  A meeting of drivers had been held prior to the event to poll them about running in the rapidly approaching darkness. The vote was to race.

Trickle experienced engine trouble on the back straight and slowed down. Adema attempted to swerve past the stalled machine, but clipped it from behind. Adema lost control and was thrown an estimated 100 feet onto the track. He got to his feet, but Team Bombardier driver Yvon Duhamel was unable to avoid a collision. His Ski-Doo struck Adema at an estimated 70mph.A second machine, driven by Joe Wolfe of Michigan, also struck Adema. Neither driver could be faulted. It was an unavoidable situation.

Adema was pronounced dead on arrival at Ashland, Wisconsin, Memorial Hospital a few hours later. Adema was the first professional snowmobile racing fatality in the sport’s history. His death stunned the industry and thousands of racing fans.

Jim was a competitor who has won favor among racing fans because of his one-man war against the gleaming factory machinery and the men in colorful, custom-tailored suits. Adema’s motorhome and trailer were no match for the factory semi-trailer vans, either. He enjoyed the image he portrayed, but in reality, Jim’s shop and expertise were a match for all but the very best factories.  He never took the time to look back upon all his achievements and bask in the respect he built for himself.

Jim missed quite a few award presentations because as soon as the race was over, he was working on his equipment for the next week. It wasn't unusual at all for him to work 17 or 18 hours a day, seven days a week, to get ready. He went to the races with one purpose- to win. He'd race anything at anytime, and when he did, he wanted to beat you. If he couldn't, he'd go home and figure out a way to do it next time. There was never any doubt about his capabilities. Besides being an adept driver, Jim was a genius in the fine art of preparation. A number of companies in the snowmobile industry were interested in hiring him because of his expertise.

Adema balked at a number of offers, however. He set a price, a substantial salary figure, which no factory was eager to pay. His change in loyalties from Sno*Jet to Yamaha came primarily because Sno*Jet was not racing.

Adema’s death re-opened all of the old and lingering questions about snowmobile speed and safety, especially those relating to the extremes involved in racing. The Snopro group got together and drew up some hard-line safety rules. The days of racing despite blinding snow, darkness and rough tracks were gone. It was time to stop playing "chicken."

Adema's death was a tragedy, and shocked the whole racing industry. He is still known as the best modified racer.

Here are some very rare photos. They were taken at Ironwood, Jim standing by his SRX in the pits.
There aren't very many photos of Jim on a Yamaha. Even looking at the photos above, this appears to be a different sled.