"I tell them about something that is really exciting, and I can promise you that it will motivate them like they have never been motivated before"
I liked the TARAus must-vote u-turn, which hasn't happened in the US version, but I don't think teams would call it "exciting."
I am wondering if maybe there is some incentive for finishing higher in the rankings on each leg? When I think of people not being really motivated, I think of teams content to repeatedly finish in the middle of the pack, or "not last." Maybe teams could get a little bonus money for the next leg if they place well?
Another twist which could motivate everyone: winning something like a "get out of jail free card." Unlike an Express Pass which is used to skip a task, or a Salvage Pass which allowed a TARAus team to keep another team in the game, this pass could be used by a team at the at the pit-stop to avoid their own elimination.