AMSOIL Tech Tips: Belt Deflection

One of the easiest things you can do to ensure your snowmobile performs at its peak level is to ensure proper belt deflection.

First, check the existing belt deflection

Put a straight edge between the clutches and pull down on the center of the belt. The proper adjustment for the snowmobile shown in the video is 1 1/4″ of space between the straight edge and belt. The belt deflection on the belt, however, is about 1 1/2″, meaning it’s too loose and requires adjustment. To adjust the belt, loosen the jam nut on the secondary clutch using an Allen wrench. Turn the adjuster counterclockwise to draw the sheaves together. Grab ahold of the belt and roll it through the primary and through the secondary. You’ll see the belt rise in the secondary sheaves, which causes it to tighten.

Take a second measurement using the same process explained above

If you go too far and the belt is too tight, turn the adjustment screw in the opposite direction. Doing so will push the sheaves apart. As you’re doing that, you’ll see the belt drop in the sheaves. This indicates the belt is loosening. The lower it rides, the looser the belt will be. Again, take a measurement and repeat the process until belt deflection is within the correct specification for your snowmobile. Once you’re finished, tighten the jam nut. Be sure to insert the Allen wrench first to hold the adjustment and then tighten the jam nut. If you just tighten the jam nut, you’re going to turn the adjuster at the same time and affect the belt deflection. With belt deflection correctly set, your sled will perform at the top of its game.