Zonghshen has had the RX3 out for a number of years now and it’s sold well in various markets under local branding, most notably in the US by the California Scooter Co as the CSC RX3.
Zongshen also has a 450cc version which is also a single-cylinder, water-cooled, four-valve motor. The RX4 450 motor made its first appearance a year ago in the Zongshen NC450 Dakar Rally bike.
Like the RX3 the RX4 comes pretty well spec’d with upside-down forks, crash bars and full luggage all as stock and if it goes anything like the RX3 it will get along better than the specs suggest on paper.
In road-going form, the RX4 450cc single makes 40hp at 8000rpm, and 37Nm of torque at 7000rpm and weighs 204kg wet, including the crash bars and full luggage.
The RX4 being used in anger
Hmm,Not a model I would go for,look here for a brutally honest review
The RX4 and the RX3S have been ridden and some thoughts are in this video.
https://www.youtube.com/watch?v=IMvhOyMuFR4
An existing RX3 owner rides the RX4, and likes it.
http://exhaustnotes.us/blog/index.php/2018/10/24/the-rx4-first-impressions/
CSC in California has released a video of ones of their riders playing around on the new RX4.
https://youtu.be/4c143qurw7s