Those are nice efforts. I had to struggle with mine, too. It was super fast to open nearly full, making part throttle an exercise in micro foot movements. And the standard "race" throttle system could not direct the cable in a linear fashion over the movement angle. So I made this:
- Linear cable pull, Euler curve progression
(Sorry it's upside down!)
Sandwiched inside the rotating bit is an eccentric using an Euler curve. When the cable starts to pull it is pulling on the large diameter end. When it is nearly done, it is pulling the small diameter section. This helps to offset the unbelievably rapid rate of change in throttle area as the valve swings through the arc.
The rod end allows the path of the cable to remain tangent to the eccentric's curve.
It's funny how frequently people become dissatisfied with throttle mechanisms!
John