While lots of people know the term 'blueprint', few fully understand exactly what it is. The name originally comes from the type of paper that technical drawings come on, which is generally blue in color.
What does this have to do with my motorcycle engine power? Well, a blueprint of an engine shows its design in very high detail, down to the last nut, bolt and measurement, so you need to make reference to the blueprint drawing to take an engine completely apart and reassemble it.
Blueprinting an engine is the process where you strip it down and refine every component to its optimum level of performance. Modern engines are mass-produced and so aren't built to precision.
Parts that are cast can have rough edges and tolerances, while weights can vary. This may only be by tiny amounts, but each imperfection adds up to a power loss when an engine is revving at 15,000rpm. Blueprinting irons out these imperfections.
A cylinder head will have its ports smoothed off to allow the gases to flow with less resistance, pistons will be balanced so the engine doesn't develop any small vibrations which can rob power, and oil-ways are smoothed to get rid of sharp corners to allow the oil to flow and the valve seats are checks, too.
In addition, every single tolerance is double-checked and everything that can be tweaked to the minutest degree is. When an engine is blueprinted, it's rebuild to the exact specifications it was designed for It's a very precisely built engine. Because of this attention to detail, the engine generates a good amount of more power.