The Dave Brown 90FS--9004 fits the 90 and the 110 YS perfectly and because of the round firewall backplate and the uneven (non square) bolt pattern it will fit the tightest of situations. even the top part of the bridge can be cut away for making room for the airbox if needed for CG purposes and it still very durable but break when you want it to. i.e. during a crash.

John