New Moto Guzzi Door Mats Available Now
I installed an o-ring between the bar end weight and the grip. I can relax my hand and the throttle doesn't move. But you have to remember to throttle back positively - there is no automatic return to idle speed - and you need to adjust for changes in terrain. But it is pretty cheap and works!
This device is so simple you won't believe how effective it is.. for about $20. from Aerostich..