I use that hole to mount a low-profile Emgo repop of an early Honda key switch. Used to use an Emgo repop of the early Harley screw post B-I-L switch, which failed after 14 years of use. The only switches available in that pattern now are the Chinese trash sold in Harley shops under the Custom Chrome label and the same POS sold under the Drag Specialties mark. I tried one of each. At around 6200 rpm the contacts on both floated, causing ignition to break up.