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1970 Boa-Ski Mark 1

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1970 Boa-Ski Mark 1
Boa-Ski knew a thing or two about branding. The Boa-Ski logo was plastered all over the sled, from the single 292cc Hirth engine to the handlebars with a unique style of brake lever.
1970 Boa-Ski Mark 1
First manufactured in 1968, Boa-Ski snowmobiles were made in La Guadeloupe, Quebec, northeast of Valcourt, Quebec – the home of Ski-Doo.

Dale Nater from Eagan, Minn., owns one of these great looking 1970 Boa-Ski Mark 1 snowmobiles, and he rides it in a lot of vintage rides. He also owns original paperwork from when the sled was sold new in Cortland, Ohio, for $695. (List price back then was $749.95.) Since then, this particular Boa-Ski has toured the snowbelt, from Duluth, Minn., to Iowa.

Bring the Boa up to speed!

Dale came across the sled when he and his friend, Lee, were shopping vintage sleds. Lee already had a single-cylinder Rupp in his bag, and he inspired Dale to begin his own search for an oddball single-cylinder snowmobile. The search ended when Dale spotted a nice looking Boa-Ski listed in the VSCA’s online classifieds. As soon as he saw it, he fell in love. The sled needed some work, but Dale had the ability to rebuild it to look just how he envisioned it.

Dale started his project by powder coating the sled’s tunnel and finding all kinds of parts that were needed to make a great looking and running Boa-Ski. He rebuilt the Hirth engine with .20 over piston rings, and he powder coated the engine bright red – the original color of the German-made 292cc single Hirth.
1970 Boa-Ski Mark 1 handlebar
Back then, almost every snowmobile came with a Tillotson carb, and the Mark 1 was no different. The motor generated 19 hp. The air-box even had the Boa-Ski logo on the cover, but Dale didn’t have an air cleaner, so he put in a GEM Ram air tube instead. Finally, the Boa-Ski logo was molded into the bright red handlebars. The best solution being to have new ones made out of aluminum to match the same size – a very durable replacement!

The 1970 Mark 1 came with a molded aluminum chaincase with the Boa-Ski logo crafted into the bottom side. There were easy upper drive chain adjustments using slots, and a nice grease fitting for driven clutch bearings. Braking is done with a floating brake pad pushing on the stationary driven clutch sheave. To make a brake adjustment, all you have to do is adjust the cable stop. The drive clutch uses kidney-type weights working with a cam-action driven clutch.

The muffler lays horizontal toward the front of the hood, with a flex-pipe exhaust going out near the right foot bracket. The removable fiberglass hood has dual 35-watt headlights. Studs are used to hold the rear of the hood securely. The seat is black with a back rest and a nice “luggage compartment” in the rear.

Track issues
The 1970 Mark 1 was made with a 151/5-inch-wide rubber track. It offered 870 square inches of traction and weighed 285 lbs. Every bogey wheel had its own grease zerk for easy maintenance. Dale had some problems with his 45-year-old track rotting apart, so he replaced it with a Camoplast 15-inch-wide Ski-Doo-style track. After finding old Ski-Doo front and rear drive shafts, Dale took off the drive hubs that hold the drive sprockets and re-welded them with the correct spacing to avoid respacing any of the bogey wheels. Although no longer entirely original, it looks and works great! Says Dale, “What fun is owning a sled you can’t ride?” We tend to agree.
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