After installing a new drive belt, we recommend that you do a "high-speed adjustment." This involves setting the Mark V to run at approximately 5200 RPM, and then adjusting the Allen screw in the speed changer to stop the movement of the quadrant (pork chop) when the Mark V reaches this speed. Because we have an additional belt supplier, we've found it necessary to make some changes and additions to the procedure.
1. Initial High Speed Setting -- Instead of setting the high speed to 5200 RPM when you have installed a new belt, set it to 4800 RPM. As the belt flexes and wears in, the high spped will gradually rise to 5200 RPM over several months.
2. Belt Position at High Speed -- If you do not have a tachometer, we recommend you adjust the high speed so the belt is riding about 1/8 inch below the rims of the motor sheaves. This is for belts that are a full 1/2-inch wide only. If the drive belt you have purchased is stamped "Gates", it is slightly narrower that 1/2". When doing a high-speed adjustment with a Gates belt, the belt should ride approximately 1/4 inch below the rims of the motor sheaves at high speed. The differences in the width of the belt and its position on the sheaves do not affect the performance of the Mark V. Provided you have done the high-speed adjustment correctly, your machine will produce RPM speeds in the ranges you need as indicated on the speed dial.
With all good wishes,
Drive Belt Installation -- Addendum to Procedure
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