Yamaha SR 250 Exhaust Valve Tappet

 
Tuning up the Yamaha a bit this afternoon.
Among other things, the exhaust valve clearance was out of adjustment.
The photo shows the rocker arm end and the tappet that pushes down on the top of the exhaust valve (the tappet gets adjusted).

This little gizmo has been faithfully doing its vital job in the operation of the engine for nearly 35 years now.
I think that's cool!