one against the brake plate between the brake plate and swingarm and one on each end of the axle

as found on Triumph

This Top Dead Center (TDC) tool makes locating top dead center on your 500/650/750 c

at deepest

7/8 inch Clamp with Micro Switch - Black Subcategory_Switches one against the brake plateKustom Tech came out with this slick addition for any of their Deluxe, Seventies, or Classic Line of master cylinder or clutch brake levers (controls not included)! Forged aluminum construction, this clamp with integrated microswitch replaces the existing clamp allowing you to have a momentary switch clean mounted right where you would need it. Available for 1" or 7 8" handlebars in 4 different finishes: polished aluminum, satin aluminum, raw