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When you're making repairs or doing maintenance on your Ski-Doo, you'll see exploded drawings at the beginning and end of each section of the shop manual. These drawings may show the torque specified for bolts or nuts next to the part. If the torque isn't shown on the drawing, however, you have to decipher the table of torque specifications using metric nut and bolt sizes and fastener grades.
Metric Property Classes and Lengths
Bolts have property class numbers stamped on their heads; nuts have property class numbers stamped on the side of the nut. Ski-Doo uses metric nuts and bolts, the heads of which are marked with property class numbers: 4.8, 5.8, 10.9 and 12.9. A metric size M3 bolt or nut is 12 mm. Bolt sizes increase in 2 mm increments. For example, an M4 is 14 mm, an M5 is 16 mm, M6 is 18 mm and an M12 is 30 mm. Compare the number on the head of the bolt or side of the nut to the pictures in the "Tightening Torque" chart marked "property class and head markings." When you find the property class number that's stamped onto the head of the bolt or side of the nut, go down the column until you reach the row for the the correct bolt length or nut size. For example, if you have an M6 bolt with 9.9 stamped on its head, go to the 9.9 picture. Move your finger down the column to the M6 fastener size. You'll see the proper torque is between 40 and 47 inch-pounds.
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Will Charpentier is a writer who specializes in boating and maritime subjects. A retired ship captain, Charpentier holds a doctorate in applied ocean science and engineering. He is also a certified marine technician and the author of a popular text on writing local history.