I had the same issue at first with mine. If yours is like mine, there is room to put a washer under the head of the bolt which will have the effect of adding 1/16" additional clearance on the thread side of the bolt while still maintaining the necessary clearance for the cotter pin.
RV-8 #81077 Super Slow Build
Dynon Skyview HDX, Titan IOX-370, Dual P-Mags, AFP FM200A FI, Whirlwind 200RV CS Prop
First Flight 11/20/2016