[Eagle7840]

My GF has a 2002 Ace 750. When I had my Spirit 750, 85mph felt like the bike was giving it all it had. We are contemplating riding the bikes out to California for a coastal trip this summer, but I'm concerned about riding 80-85mph for 4-6 hours straight (West Texas has 85mph speed limits).

Am I just over thinking this, or is this a bad idea on her bike?

You don't have to ride to the speed limit. I'd suggest 65-70mph giving her room to downshift to accelerate for passing, keeping engine and tire heat down, fuel mileage and enjoying the scenery and ride.