At the rear base of the cylinders of the A10 there is a vertical screw pointed downward toward the lifters. According to the BSA parts catalog it has a ball beneath it, and a horizontal peg.
The part numbers are
10167-0276 or 10267-0949 screw
What are these parts and what do they do? And does it matter if the ball is missing?
My engine is all back together and I remember nothing of the ball or peg. And the last time I rebuilt an A10 was decades ago.
1963 BSA Rocket Goldstar, 1969 Triumph Tiger, 1969 Norton Commando, 2017 Yamaha FZ07, 1955 Ford Thunderbird