The rocker box screw is important as it secures the rocker inspection cap retainer to the top of the rocker box. It also serves as the retaining screw for the gearbox inspection cover on later pre-unit Triumph 650 models.
The set of four screws are 1/4″-26 TPI x 3/8″ “cheesehead” type, made in the UK by LF Harris.
The screws are used with fiber sealing washers to fit the spring clips to the rocker box tops. The spring clips secure the threaded rocker inspection caps. The screws also are used to secure the inspection covers on pre-unit gearbox covers.
The screws are threaded directly into the top of the rocker boxes with a sealing washer and spring clip under the head of the screws.