Torque settings for bolts
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Always use the proper grade fastener. You should use at least grade 5 fasteners on almost everything on your motorcycle. Bolts are graded by tensile strength and are easily identified by the number of slash marks on the head of the bolt. The more marks the higher the quality. Hardware store bolts with no markings on top are usually soft, mild steel, grade 2 qualities and should be avoided like the plague.
Another thing to watch is torque specs. A bolt that has been over tightened can be just as lethal as one that hasn't been tightened enough. A bolt that has been tightened beyond recommended torque specs can easily break in service. In other words the soft grade 2, 5/16-18 hardware store bolts that are attaching the bottom of your sissy bar to the back legs of your rigid frame are shaky enough to begin with, they get downright lethal when you tighten them up as tight as you can get them with a couple of 10" wrenches. Keep in mind that torque specs will be less for bolts that have oil or lubricate on them than for clean, dry bolts. Use the following tables to determine what grade of bolt you are working with and how tight to torque it.
When a bolt is installed, the nut (over a washer) should be turned and not the bolt's head. Unless a torque wrench is used the tendency is to under tighten large bolts and over tighten small ones. Suggested torques is given below. These suggestions do not apply if the bolt or nut has been specially lubricated. Experiment is the best way of determining torque values for small fasteners. Pick at least 7 sets of parts at random and assemble them, torque the fastener until it fails. (The values at failure should fall within a fairly narrow range; if they don't, something is amiss with the parts, the torque wrench, or your technique.) Find the average failure value, and then take 65% of it.
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