The 790 adventure come standard with a simple steering damper. It’s fine for the road, but for serious off road junkies it is not enough. There are other options out there that allow for more fine tuning (aka, dampening when going away from center, but not the other way, etc). There is a hole with a plastic plug right under the handlebar just for that purpose.
All those dampeners are going under the handlebar, this means that their mounting kits are also raising the handlebar and probably moving it forward at the same time. Keep an eye on handguard, as moving the bar forward may cause them to hit the instrument panel…
Also, if you fit one of those you need to remove the original dampener.
See also this thread on advrider.
Hack the original
The stock steering damper can be upgraded by changing out the stock lightweight oil for 10 or 15 weight fork oil. There are a few YouTube video showing the process. This make it harder to move the handlebar in all directions. Ok for road usage, probably not ideal off road.
For road only usage, Hyperpro offers a dampener (In multiple colors!) which can be adjusted in resistance as a drop-in replacement.
The most talked about, and a well proven solution on a number of bikes. With slow and high speed separate circuits, and in business since forever. $660 for the device and a mounting kit specific for the 790. The mounting kit is massive as it also adds rubber damping to the handlebar itself.
There are two versions of the Scott damper, a road version (with a R stamped on the body) and an off road version. You probably want the off-road version.
A simpler, lighter and cheaper mount is available from TripleClamp Moto for £160, or £475 with the device in the UK, $170 in the US, and €195 in the EU (prices are indicative, visit the site for exact price).
Simpler solution, with only one simple button, this damper will not protect you as well against hitting a rock a speed as it lacks the high speed circuit of the Scott’s. But still, it probably does most of the job, releases when hitting a 15º angle. $525 with mounting kit.
From Australia, another simple damper with one button and a mounting kit. AU$645 without shipping.
Chris Birch’s own, so you’ve seen this device in multiple videos already. XRC is a NewZealand company. Available online here ($NZD980, aka around $570), ships worldwide (not sure about the post specific to the 790).
More pictures on advriders.