Here are the 2 upgrade bottles - the funky looking shape needs a minor mod and DIY see links below
This is a 100% direct replacement for the RX3 and has the rubber flip open lid.
https://www.ebay.com/itm/303025898703
This is the RX3S version (might fit on inner guards on VERY late model)
I mounted it from the bolt where the frame for front nose mounts and used an angle bracket to the coil bolt, some DIY needed but super easy to fill.
https://www.ebay.com/itm/303025901309
http://chinariders.net/showthread.php?t=16308&page=8
http://chinariders.net/attachment.ph...1&d=1536316017
http://chinariders.net/attachment.ph...1&d=1536316017