A.Worn intake valve guides B.Pitted pre-combustion chambers C.Loose valve tappets D.High exhaust back pressure
A.fuel knock B.increased power C.low compression pressure D.high exhaust temperature
A crankshaft whose center of gravity coincides with its center line is said to be() Ⅰ.statically balanced Ⅱ.dynamically balanced
A.Ⅰ only B.Ⅱ only C.both Ⅰ and Ⅱ D.neither Ⅰ nor Ⅱ