Abstract: A throttle stop collar for a manually-operated throttle lever includes a resilient ring defining a cylindrical cavity therethrough, the ring sized for snug sliding fitment over a handlebar handgrip. The ring has an outer surface eccentrically disposed relative to the cylindrical cavity. The ring is sized to fit between the throttle lever and the handlebar in a path of the throttle lever when depressed by a user so as to selectively obstruct and limit a range of motion of the throttle lever when rotated between a closed-throttle idle position and an open throttle position.