What are these for.

[peebee]

https://imagizer.imageshack.com/img922/4023/fy905r.jpg

Can anyone tell me what these
bolts are for. They certainly don't clamp the cases together, but look like they are something to do with the hydraulic lifters in some way.
When I tried to adjust the tappets by the manual one side got a noisy rattle on . I have adjusted and repaired many engines in my 55 years of biking so I am certainly not a novice where old fashion engines are concerned. So being stumped I talked to a dealer (rare species these days) and he fixed it for me but never said why it did that or how he fixed it. His advice was leave the buggers alone they will look after themselves no problem. Is there any body on this forum with intimate knowledge of this engine who has performed this adjustment before and can tell me for definite where the pit falls are

 

[TonyA]

Black one is hydraulic lifter guides (one on each side) and larger silver bolt is the oil the oil gallery drilling. You can read your oil pressure there . Are you using the newest spec of 2.25 turns for the lifters ?? Old spec was 1 turn cold engine from just touching.

https://imagizer.imageshack.com/img922/4023/fy905r.jpg

Can anyone tell me what these
bolts are for. They certainly don't clamp the cases together, but look like they are something to do with the hydraulic lifters in some way.
When I tried to adjust the tappets by the manual one side got a noisy rattle on . I have adjusted and repaired many engines in my 55 years of biking so I am certainly not a novice where old fashion engines are concerned. So being stumped I talked to a dealer (rare species these days) and he fixed it for me but never said why it did that or how he fixed it. His advice was leave the buggers alone they will look after themselves no problem. Is there any body on this forum with intimate knowledge of this engine who has performed this adjustment before and can tell me for definite where the pit falls are