Summary and Analysis, hold on....
Config #1 - Stock XS1 worm, 1.3" clevis hole distance
Config #2 - Arm bent down 0.4", 1.3" clevis hole distance
Config #3 - Arm bent down 0.5", 1.7" clevis hole distance
Config #4 - Arm bent down 0.5", 1.7" clevis hole distance, modified cable/elbow entry angle
Config #5 - MikesXS original worm, 1.35" clevis hole distance
Config #6 - MikesXS original worm, 1.75" clevis hole distance
Config #7 - MikesXS modified worm, 1.20" clevis hole distance, modified cable/elbow entry angle
Config #8 - MikesXS modified worm, 1.60" clevis hole distance, modified cable/elbow entry angle
Config #9 - Ultimate XS worm, 1.65" clevis hole distance, modified cable/elbow entry angle
#1: Pull-test = 25 lbs, Actuator travel = 0.062", Cable tension = 150 lbs
#2: Pull-test = 18 lbs, Actuator travel = 0.064", Cable tension = 108 lbs
#3: Pull-test = 14 lbs, Actuator travel = 0.046", Cable tension = 84 lbs
#4: Pull-test = 13 lbs, Actuator travel = 0.051", Cable tension = 78 lbs
#5: Pull-test = 15 lbs, Actuator travel = 0.045", Cable tension = 90 lbs
#6: Pull-test = 12 lbs, Actuator travel = 0.034", Cable tension = 72 lbs
#7: Pull-test = 16 lbs, Actuator travel = 0.062", Cable tension = 96 lbs
#8: Pull-test = 13 lbs, Actuator travel = 0.040", Cable tension = 78 lbs
#9: Pull-test = 14 lbs, Actuator travel = 0.058", Cable tension = 84 lbs
Well, this is a bunch of mumbo-jumbo, how to make sense of it all?
We can calculate a scoring value for each, and sort on those values. Since we want more actuator travel, but less lever effort, let's try a simple ratio, like plunger travel in mills (0.001", millinch, thousandts-of-an-inch) per pound of lever effort. In the ideal/frictionless environment, the XS clutch mechanism would get close to 10 mills (0.010") for each pound of pull, so 10 is the perfection value, everything else comes below that. This is, in a way, a measure of machine efficiency, on a scale from 1 to 10, and is what we're pursuing.
New list, showing mills/lb scoring factor:
#1: Travel = 0.062", Pull = 25 lbs, Mills/lb = 2.5
#2: Travel = 0.064", Pull = 18 lbs, Mills/lb = 3.6
#3: Travel = 0.046", Pull = 14 lbs, Mills/lb = 3.3
#4: Travel = 0.051", Pull = 13 lbs, Mills/lb = 3.9
#5: Travel = 0.045", Pull = 15 lbs, Mills/lb = 3.0
#6: Travel = 0.034", Pull = 12 lbs, Mills/lb = 2.8
#7: Travel = 0.062", Pull = 16 lbs, Mills/lb = 3.9
#8: Travel = 0.040", Pull = 13 lbs, Mills/lb = 3.1
#9: Travel = 0.058", Pull = 14 lbs, Mills/lb = 4.1
Finally, sort the list by score, highest score first:
# Score Travel Pull Description
#9: 4.1 0.058" 14 - Ultimate XS worm, 1.65" clevis hole distance, mod cable entry angle
#4: 3.9 0.051" 13 - XS worm, arm bent down 0.5", 1.7" clevis hole distance, mod cable entry angle
#7: 3.9 0.062" 16 - MikesXS worm, arm bent down 0.5", 1.20" clevis hole distance, mod cable entry angle
#2: 3.6 0.064" 18 - XS worm, arm bent down 0.4", 1.3" clevis hole distance
#3: 3.3 0.046" 14 - XS worm, arm bent down 0.5", 1.7" clevis hole distance
#8: 3.1 0.040" 13 - MikesXS worm, arm bent down 0.5", 1.60" clevis hole distance, mod cable entry angle
#5: 3.0 0.045" 15 - MikesXS original worm, 1.35" clevis hole distance
#6: 2.8 0.034" 12 - MikesXS original worm, 1.75" clevis hole distance
#1: 2.5 0.062" 25 - Stock XS1 worm, 1.3" clevis hole distance
Having ridden around with all these different configurations, and knowing the zones for clutch engagement and finding neutral, and experiencing the typical XS 'expanding case' slackening issue, I personally wouldn't use any configuration that didn't produce at least 0.050" of travel. Would also prefer the 'lighter' clutch pull, selecting those under 18 lbs. So, weeding those out we get:
Selected clutch worm configurations:
# Score Travel Pull Description
#9: 4.1 0.058" 14 - Ultimate XS worm, 1.65" clevis hole distance, mod cable entry angle
#4: 3.9 0.051" 13 - XS worm, arm bent down 0.5", 1.7" clevis hole distance, mod cable entry angle
#7: 3.9 0.062" 16 - MikesXS worm, arm bent down 0.5", 1.20" clevis hole distance, mod cable entry angle
Just so happens, these are the top 3 scorers. So, I'm currently using #9, the 'ultimate' XS worm. Works fine so far.
=== End of clutch worm experiments, for now ===