I’ve replaced the MM144 drive belt on my #4 and adjusted the motor mount to accommodate it. My question is: What is the proper belt tension? How do I how measure and adjust it accordingly?

3 thoughts on “#4 Drive Belt Replacement”

  1. Is the ‘span of the belt between the pulleys’ measured from the center of each pulley?
    Thanks Paul!

  2. First, check that the pulleys are aligned and that the set screws are tightened. The belt should have minimal deflection or give. Too much deflection and the belt may slip, too little deflection causes wear on the bearings of the pulley shafts. There are tension test gauges, but these are unnecessary for your purposes. It will be fine to guestimate 1/64″ deflection per length of span of the belt between the pulleys.

    The main thing is that the belt doesn’t walk or travel side to side while powered on.

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