Which of the following is NOT one of the four strokes in a four-stroke cycle?

In a four-stroke engine cycle, there are four distinct strokes that describe the process an engine undergoes during one complete cycle of operation. These strokes are intake, compression, power, and exhaust.

The intake stroke is where the air-fuel mixture is drawn into the cylinder, preparing it for combustion. The compression stroke follows, where this mixture is compressed to increase its temperature and pressure, making it more efficient for combustion. The power stroke is the phase where the compressed mixture ignites and expands, forcing the piston down and creating power for the engine. Finally, the exhaust stroke expels the spent gases out of the cylinder, completing the cycle.

The term "revamp" does not pertain to any step in the four-stroke cycle. Hence, it is the option that correctly identifies something that is not a part of the cycle, as it does not align with the established terminology or processes associated with engine operation. This understanding is crucial for anyone studying mechanics or functioning of internal combustion engines.