comments:
anonymouslosername posted on r/motorcycles2w
https://www.amazon.com/Crampbuster-CB4-Throttle-Mounted-Motorcycle/dp/B001L9KI56/ I've found these to help, having done a few trips on my ninja. Alternately, you can often cheat with one of those thick "hair tie" bands squeezed between the throttle grip and the housing as a ghetto cruise control
Haggi999 posted on r/twoxriders2w
Search the net for "Trottle assist, cruice control, crampbuster". They really work. Example: Amazon link