Typical Staged Sportster Engine Upgrades ¹⁾

Stage 0: Stock = HP- 40 for 883, HP- 50 for 1200 (average)

Stage 0.5 (also known as “The Harley Tax”)= HP- 50 for 883, HP- 60 for factory 1200 (Example)²⁾

• Stock plus:
  • High flow air Cleaner OR
  • SE Slip-On Mufflers or equivalent

Quote: Stage 1 and Harley Tax are synonims and include Pipes, Air Filter and Carburetor re-jetting/ ECU re-mapping ³⁾

• Stage 1.0 = HP- 60 for 883/1200, HP- 65-70 for factory 1200 (Example)⁴⁾
• High Flow Air Cleaner AND
• High Flow Exhaust AND
• Fuel/Air ratio adjustment : Jetting for carburetor, modify fuel tables in ecm with EFI bikes.

This is just examples of what has worked on some bikes. Each motor may be different in it's own unique way.

883 Engines:

• Carbureted / Year Model / Jetting / Mods:
  • .
  • .
  • .
  • .
• EFI:/ Year Model / Jetting / Mods:
  • Screamin' Eagle Air Cleaner/ Screamin' Eagle Slip on exhaust
  • .
  • .
  • .
  • .

1200 Engines:

• Carbureted / Year Model / Mods:
  • .
  • .
  • .
  • .
• EFI:/ Year Model / Mods:
  • .
  • .
  • .
  • .

Stage 1.5= HP-65 for 883/1200, HP- 70 for factory 1200 (Example)⁵⁾

• Stage 1 plus:
  • Andrews N2 cams (mild)

Quote: Stage II: Stage I plus cam upgrades ⁶⁾

Quote: Stage II: Camshaft, Larger displacement, Higher compression ⁷⁾

• Stage 2: Stage 1.5 plus: (Example)⁸⁾
  • Andrews N4, N8, or SE bolt-in cams instead of N2
  • SE S1 Lightning or other bolt-on +/- 10:1 heads
  • HP=75
    • Options:
      • 2 into 1 header system, add +/- 7 hp
      • SE carb (or equivalent), add +/- 3 hp
      • XR750 (or other) valve springs, no gain
      • Stage 2.5: Stage 2 plus
      • Professionally ported 10:1 or higher heads
      • Matching (to head) domed pistons
      • XR750 valve springs or SE cam kit
      • 2 into 1 header system
      • SE,S&S Super E, or Mikuni HSR42 carb
      • HP=90+
    • Options:
      • big valves (big twin size), add +/- 5 hp

Quote:Stage III: Its on like Donkey Kong ! ⁹⁾

Quote: Stage III: Boring and/or Headwork and/or Forced Induction and/or Nitrous ¹⁰⁾ Stage 3 = HP- ????

• Stage 2.5 plus:(Example)¹¹⁾
  • Big-bore cylinders and pistons and/or
  • Stroker kit and/or
  • Nitrous injection and/or
  • Supercharging
  • Options: many

• Displacement: pi x (radius squared) x height (example: 4 inch bore, 4 inch stroke) = 3.14159 x (2 squared) x 4 = 50.265ci of displacement per cylinder
• Cubic Centimeters to Cubic Inches: cc ÷ (2.54 cubed) (example: 1200cc) = 1200 ÷ (2.54 cubed) = 73.23ci
• Cubic Inches to Cubic Centimeters: ci x (2.54 cubed) (example: 100ci) = 100 x (2.54 cubed) = 1638.7cc
• Horsepower: (torque x rpm) ÷ 5252 (example: 80 ft-lbs at 4000 rpm) = (80 x 4000) ÷ 5252 = 60.93hp
• Torque: (horsepower x 5252) / rpm (example: 100hp at 4000 rpm) = (100 x 5252) ÷ 4000 = 80 x 4000) / 5252 = 131 ft-lbs.

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