"Where the history of snowmobiling comes to life"
1972 Sno Jet Thunder Jet (Water Cooled By Jim Adema)

1972 Sno Jet Thunder Jet (Water Cooled By Jim Adema)

1972 Sno Jet Thunder Jet: Thetford Fiberglass Industries built their first 25 Sno Jet sleds in October, 1964. By 1970, Sno Jet was into racing with the GT I-II-III series with the GT III using a 793cc Hirth Honker motor.
In 1971, an advanced development team headed by Chief Engineer, Don Aho, developed the 1971 Thunderjet. The original Thunderjet had many innovative features such as a low engine placement, aluminum chassis, Sno Jet clutching and utilized the Yamaha 440R free-air motor. However, the machine was heavy and unstable. By 1972, Don Aho, with the help of a young racer from Michigan named Jim Adema, made the '72 Thunderjets much lighter and more stable. 100 each of 4 models were produced for racing. They were the 295cc, 340cc, 440cc, and 650cc models.
To say the '72 Thunderjets were successful would be a big understatement. They took over the race circuits. In Jan. of '72, Jim Adema lapped the entire field in one race at the Karwatha Cup in Peterborough, Canada and won the Canadian Cup on points. At Eagle River in '72, Thunderjets won the 800cc Cross Country and ruled the ovals with wins in the 295cc, 340cc, 440cc, and 650cc classes. The engine placement in the '72 Thunderjets was to influence the design of all snowmobile design going forward.
Thunderjets were produced in 1973 for the 295cc, 340cc, 440cc, and 650cc Mod classes. In 1974, the Thunderjet was produced as a SX-340-45hp model. In 1975, the last year for Thunderjets, they were all 440cc models.

Top of the Lake Snowmobile Museum News Release-2023 On September 22, 2023 the Michigan Arts and Culture Council (MACC) in conjunction with the National Endowment for the Arts (NEA) announced it would be generously awarding the Top of the Lake Snowmobile Museum in Naubinway an $8750 grant for operational support during 2024. MACC uses a peer review process to award grants. More than 700 organizations across the state applied for funding. Each grant application is competitively judged; awardees are chosen to ensure Michigan residents and visitors have access to the most authentic aspects of local arts and culture. Organizations receiving a grant award from MACC/NEA are required to match those funds with other public or private dollars. The Top of the Lake Snowmobile Museum receives a great deal of donated monetary support through its memberships and visitors and plans to use these funds to match the MACC grant award. There are 141 active museum members not including lifetime members and more than 7000 visitors just last year.

The museum has plans to bring more local art-related activities to our conference room and develop a program for groups with special needs. This support will go toward the cost of wages and advertising for these activities. On Sept 20, 2019, The Top of the Lake Snowmobile Museum was awarded a grant of $12,500 for Operational Support from the State of Michigan Council for Arts and Cultural Affairs (MCACA) and the National Endowment for the Arts (NEA – ART WORKS). The grant was awarded through the MCACA peer review process and was one of 561 applications to compete for MCACA fiscal year 2019 funding. The grant requires a 1:1 match and helped the museum leverage the $12,500 of support from its annual income and the many donations from supporters. In particular the museum has received grants from the Graymont Community Economic Development Fund and the Sault Ste. Marie Tribe of Chippewa Indians. It has also received significant donations from the Antique Snowmobile Club of America, The Midwest Vintage Snowmobile Shows, Inc., many snowmobile clubs, several recreational and snowmobile shows, the museum’s internal $1,000.00 Challenge, and many museum members. The grant funds will be applied to museum operating costs. Applicable costs include internal operations, marketing, travel to shows within the State of Michigan and cost of employees. The MCACA peer review process allows for each grant applicant to be competitively considered by a panel of in-state and out-of-state arts and culture professionals. This ensures the taxpayers, who support this project through legislative appropriations, and all other visitors or residents in Michigan will have access to the highest quality arts and cultural experiences. A complete list of grant awards around the state is available by contacting MCACA at (517) 241-4011, or by visiting the MCACA website at
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Top of the Lake Snowmobile Museum
P.O. Box 2
W11660 US-2
Naubinway, MI 49762
Hours: 906 477-6298
Appointment: 906 477 6192

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