Yes I had the same trouble as did a few other caps, what year R3 you got? I had to remove the little brackets from the seat and build them up a little with some washers. Just make sure when you build out those brackets with washers that the screws remain long enough to hold the brackets on. You will have a hard time getting the seat on until the seat breaks in a little up where it contacts the fuel tank and those rubber grommets wear in a little. I also had to bend that bracket a little too. Your rear fender and fuel tank paint is going to get destroyed by that seat, get yourself some 3M clear protectant film and put it where the seat contacts the fuel tank and where those rubber grommets contact your fender. I don't know, it may help protect the paint in case you want to get a custom solo seat or something else in the future. Try those things and let us know.
PM Juggernaut, he attached his snorkel intake and OEM seat bracket to his Corbin seat somehow, didn't end up using Corbin's ****ty bracketry.