I'm hoping to get a Kona Operator soon, and want to fit some boxxer races to it. My dilema is that obviously the bottom cup of the headset is going to fit a 1.5" steerer (tapered headtube), and the boxxers will obviously be 1.1/8". From what I've read about I could get a 1.18" crown race to fit the headset (FSA Orbit 1.5 Zero Stack) but my problem is I'm not totally sure. If I can avoid buying a completely new headset that would be great as I don't want to waste the perfectly good brand new one fitted.
tl;dr
What can I do to the bottom part of an FSA Orbital 1.5 Zero Stack headset so that it will accomodate Boxxer Races.
No he isn't. Go on Konaworld, it has the exact geometry and sizes for the frames. Its exactly the same for the FR, DH and Supreme. Same frame, different components.
Look at the links I put. Obviously a stock FR put next to a stock DH will have a steeper head angle, but thats because the FR has domains and the DH has boxxers, but the FRAME is exactly the same, except for the shock.