• The introduction of the Excelsior Super X motorcycle was the most significant motorcycle development of 1925, according to Daniel K. Statnekov, author of the "Pioneers of American Motorcycle Racing." Originally designed by an employee in Harley-Davidson's engineering department, the Excelsior Super X was an instant hit in the 1920s marketplace. The Excelsior-Henderson Motorcycle Company was founded almost 70 years later, and in 1999 produced a new brand of Super X motorcycles based off of the popular 1920s model.
  
  

Engine Type

• The 1999 Excelsior Henderson Super X has a large two-cylinder 50-degree X-twin engine. The term "X-twin" refers to the crossed configuration of the two cylinders, which are placed together at a 50-degree angle.
  
  

Displacement

• The 1999 Super X's engine has a displacement of 1,386 cubic centimeters. The displacement is the volume that shifts within the engine's cylinders as the pistons alternate between their highest and lowest positions.
  
  

Bore and Stroke

• The engine on Excelsior Henderson's 1999 Super X model has a bore of 3.66 inches and a stroke of 4.02 inches. The bore refers to the total diameter of each cylinder. The stroke is the total distance that the piston moves inside each cylinder.
  
  

Compression

• The Super X engine has a compression ratio of 9.2:1. Each cylinder's piston compresses a certain amount of volume when it moves back and forth. This compression ratio compares the volume each piston condenses in the cylinder -- 9.2 cc -- in relation to every 1 cc of volume that it does not condense.
  
  

Fuel System

• The engine for the 1999 Super X utilizes a port sequential, closed loop fuel injection system. In a port sequential fuel system, each cylinder receives a unique amount of fuel mass. Each fuel mass injection corresponds with the cylinders' intake cycles.
  
  

Intake and Exhaust

• The 1999 Super X engine has four valves per cylinder and a dual overhead cam. Thus, the Super X uses a total of four valves for the engine's intake and exhaust. One camshaft opens and closes the two intake valves, and another camshaft opens and closes the two exhaust valves.