The cam followers.
For same insane reason the original Bullet design was slimmed down from ⅜" to 7mm and a previously fine component was replaced by something more fragile.
The fix is to fit a set of iron barrel cam followers, though the outside of the guides need turning down to fit the smaller diameter holes in the AVL crankcases. You also need to modify a set of iron barrel Bullet push rods to take the AVL push rod tops.
Here's an AVL timing side crankcase half modified for me by Bullet Whisperer, also note the adjustable cam spindles have been replaced by plain spindles. Not essential, but this is one thing less to adjust or worry about coming undone, but needs a ⅝" reamer putting to the cam spindle holes in the timing cover.
The oil sight glass tube is an attempt to get away from dip-stick roulette...
For what it's worth the crankshaft I'm using on this one has been rebuilt with a UK-made big end pin and sleeved con-rod, and there will be no electric start to worry about. I will be putting a Champion plug in it, though.
A.