I do not know about silver oil, white is another story. On another note, it sure looks as if your intake manifold is leaking. Start your bike and spray some brake cleaner at the intake manifold cylinder area. If it revs up, its leaking. I would recommend getting a leak down kit from motion pro, check your head and bottom end. I would also carefully inspect the water pump seals and shaft. Could the silver be anti seize someone left on the stud? Mine is gold, but it might be something similar. The hole to the left of the fuel inlet, is that a sealed cap where the air screw would be? That bike appears to have the adjustable exhaust valve tensioner, and the adjustable choke knob?