I had the engine overhauled around 40K KM ago. It is showing slight loss of power (like 10%) and tappet noise has increased. I am using Caltex 10w30. In summers I use Zic 10w40.
Could it be that the oil pump is weak.
The engine is producing vibration, noise and has trouble with heights (knocking has started).
Knocking means that clutch plate is fine but engine is having trouble?
Plugs are checked and they are always red (not black).