There are some engines like the Harley-Davidson Twin Cam that just won’t quit. Certainly not the Twin Cam 120R installed on a 2012 Road King.

I’ve had the opportunity to tune this engine twice. I did the first tune when the engine was in its original configuration that includes SE 266E cams, while I have done the second tune after the SE cams were replaced with S&S MR103 cams. The reason the owner decided to replace, I might add wisely, the SE 266E is due to their poor low to mid-range drivability.

Here is the latest configuration of the Screamin’ Eagle 120R Crate Motor:

  • 120″ c.i.,
  • 10.5:1 compression,
  • Screamin’ Eagle oversized oil pump,
  • 64mm Screamin’ Eagle throttle body,
  • 5.5g/s injectors,
  • S&S MR103 cams,
  • S&S Teardrop air filter,
  • 2:1 Bassani exhaust.

The following graph shows the torque/power values and their trend measured at the wheel on the DynoJet dyno and obtained after a rather complex but adrenaline-filled tuning process. Yes the Twin Cam won’t quit, yet.

Torque is expressed in N-m