I think your looking at the wrong arms
![Wink ;-)](./images/smilies/icon_e_wink.gif)
!
You can see the pushrod and rocker arm, and 3rd spring arangment
edit - another look at the picture. Above the airbox, is that secondary channel for the gearbox cooling? Looks like a nice arrangment, clean. I always had wondered about the airbox shape these days. How crucial is it to get equal pressure across the intake valves?