Bully Spring Height Gauge Instructions

You will find this gauge to be very helpful in accurately setting the spring heights of your disk clutch.

The gauges are pre calibrated at the factory for the Bully clutch. If you wish to check the calibration, or wish to re-calibrate the gauge for use on another brand of clutch, follow the instructions below.

To calibrate your gauge:

Locate the tallest knurled knob (it is found on the top of the indicators shaft) and turn it counterclockwise until the needle on the small dial will go to the left of its zero point and the large needle is pointing straight down. Next loosen the short knurled nut that holds the face plate in position. Then set bottom of the gauge on a flat surface and turn the face until the needle lines up with the red number 40. This method takes into account the .040" thickness of the Bully spring retainer. On other brands of clutches you will need to measure the thickness of the spring retainer in thousands of an inch and substitute that dimension for the 40 in our example. Horstman�s are generally around .065". Jammer clutches may vary from Horstman�s. For complete accuracy measure your individual clutches retaining washers. Retighten both knurled nuts, and the gauge is calibrated.

NOTE�..The gauge indicates the highest point on the TOP of each spring retaining washer.

When reading the gauge, first look at the small dial inside the larger dial. This dial reads in 1/100ths of an inch. Next to read tenths and 1/1000 of an inch, look at the large dial and read the black numbers.

On the Bully clutch, � of a turn of all six screws will equal approximately 125 RPM; this equates to about .010" on the gauge. On an MDC-400 clutch, � of a turn of the screw will equal 100 RPM. This equates to about.007" on the gauge.

Many clutches are inconsistent on their spring heights; variances of .060" are common. On a four-stroke clutch, this can mean a difference of 750 RPM on the stall speed of a clutch. Chatter, warping, slippage of the friction disks and damage to the lever support plate, can all result from miss adjustment. We suggest all of the spring heights be adjusted to within at least .004� of each other.

If you are satisfied with your clutch�s engagement rpms, but the springs are at varying heights, check the spring heights with the gauge and record them. If they are inconsistent more than .002", add all of the readings together and divide the sum by the number of springs on the clutch. This will give you the average spring height. If the springs are then reset to this reading the clutch engagement will remain at the same rpm.