My researches give a pushrod length of 180mm for inlet, 205mm for exhaust (again, do your own checks) In his book BSA Twin Restoration, Roy Bacon says valve caps were fitted to the longstoke engine, but does not state whether they were fitted only to inlet, exhaust or all four valves. However an exploded line drawing on Page 38 of his Twins Restoration shows caps on all valves. Help from the parts catalogue in the Literature Section lists caps 65 209 fitted to all valves on the A7, but none to the Star Twin....The actual valves listed for the two models are different.
Drawing also shows pushrods fit cup down, plain end up to the rockers. The valve gear itself is broadly the same as later engines which do not have caps. Worth checking the rocker arms are the correct parts, match as pairs and one has not been strained.
Camshaft and followers with ball end tops reappear on the later unit engines, Page 95.
Longstroke Rocker Part Nos... Left Side Right Side
Inlet 67 45 67 46
Exhaust 67 47 67 48
Methinks a pushrod from any old school OHV car engine could be adapted in the absence of the genuine article. Your local engine reconditioner may have a few in the junk pile.
All the followers are the same. Overall length 76mm. Unworn tappet block is 12mm deep, Shank of follower from top of the block to top of ball end is 64mm. Caliper and eye, measured on parts to hand.
Swarfy.
