This video highlights the main issues encountered when installing the US Carburetion (Type C) trifuel conversion kit on a Habor Freight Predator generator.
Note that since this video was recorded 1) the converter was moved over (so the generator's wheels could be installed) and 2) the steel elbow in the pigtail (used tap the natural gas) was replaced with brass piping (since the steel corroded).
Also, something not in the video that one of the comments mentions... inserting the adapter requires a longer screw be used to connect the bottom of the air filter (or another way of securing).