It must be very difficult to seal the Conti tires 
Maybe I switch to Michelin 26" latex tubes...
Conti RaceSport tires can be
tough to run tubeless - I've run the RaceSports, and their sidewalls are as thin as paper. The previous SuperSport versions were even worse, I'd sometimes need double the sealant to get them to seal up the first time, and they usually wouldn't seal until they were ridden. Setting them up the first time, you'd see little dots of sealant forming all over the sidewall! The RaceSport isn't quite as bad as the old SuperSports, but still can be a challenge. The "standard" Conti tires, or the ProTection - I've found those much easier to set up tubeless because of the thicker sidewalls.
With the RaceKing RaceSports and ZTR Crests, I'd say there's no reason you can't run tubeless, it's just going to take some doing. Start with a double dose of Stan's sealant (two scoops or two of the small bottles) and give it at least a ride or two before they seal up fully. You'll want to bring a pump with you on the first ride, at the very least. Once it
does set up, though - those things can be sublime. Those super thin sidewalls and no tubes means one of the most crazy supple MTB tires I've ever ridden.
