A vehicle including a linkage-based motion control system for varying a parameter (e.g., velocity) of the vehicle as a geometric relationship between a vehicle input (e.g., velocity control lever) and a vehicle output (e.g., drive train) is modified. In one embodiment, the control system provides a linkage that allows a fixed level of input applied to the control lever to produce a repeatable output to a variable drive unit even as the drive unit is moved relative to the control lever. In another embodiment, an adjustable stop for use with setting a terminal position of a control lever (e.g., a velocity control lever) is provided. Accordingly, the maximum potential speed of the vehicle may be adjusted (e.g., reduced) without altering the speed of the vehicle engine.
