Ignition Modules
HI-4 by Crane

HI-4 Ignition Module

The Crane HI-4 ignition system comes in several different variations. The original HI-4 modules replaced the ignition sensor located inside the camshaft nose cone and required some rewiring of the bike. This unit was available as a 50 states, emissions legal unit and the 'race only' unit. The most recently released unit (HI-4E) replaces the stock HD ignition module, requiring only that it be plugged into the stock wiring harness.

While Bike Tech does not have before and after comparisons for the stock HD module vs. the HI-4 module(s), it does have experience with the original HI-4 race module. Many of the features of the HI-4 are much more important on high-compression, high horsepower bikes than would be on a stock bike or one with a mild cam (EV-13 or Fireball 300). The variable adjustment for the advance curve allows you to tune the bike to just below the point of detonation in the mid-range power band.

The ability to vary the rear cylinder timing can result in several horsepower difference on high power bikes. Making this adjustment is tedious and time consuming since the expected adjustment figure will be less than a degree of timing. From experience, 1/2 degree of timing adjustment on the rear cylinder is a large adjustment.