For both the kart and the engine I would suggest calling OTK Kart USA.

You might have luck with a kart that’s still in production, but there doesn’t seem to be many formal service documents in karting.

I used to run a Vortex ROK TT and recall struggling to find a manual as well (granted this was a few years ago).  I ended up calling a few places that either sold Vortex parts and/or rebuilt them and I was able to at least get answers to my specific questions even though they didn’t have manuals.  I believe Comet Kart Sales and J3 Competition were who I contacted…

As far as the Kosmic kart goes I’m not much help.  Comet Karts Sales sells the chassis line so they may be a good source of info (in addition to asking about the Vortex).

All you need is the general knowledge of someone who’s mechanically inclined. If you pump kart shop guy for info, make sure you follow guy code and buy something from his shop.

Gif