The BoosterPlug is the smarter tuning choice, when you want to upgrade the rideability on your Harley Davidson Road King Special FLHRXS without spending a fortune.
Compared to the Power Commander, the BoosterPlug offers similar or better tuning results for must owners - at a much lower price and without the complicated setup.
Installation couldn't be easier - The BoosterPlug comes with the correct connectors to let you plug it in to the bikes wire harness. No programming required.
There is no better way to upgrade your riding experience:
- Much better and softer throttle response
- Better acceleration
- Remove the low speed surging
- Removes the weak idle and stalling issues
- Far less popping in the exhaust on deceleration
This version of the BoosterPlug tuning module covers all versions of the Harley Davidson Road King Special FLHRXS with the Milwaukee 8 engine (2017 to 2020).
Please note that we can not build a BoosterPlug for the "2021 and newer" model due to new emission regulations. You can see the detailed explanation here
General Installation Instructions
Bike Specific Installation Instructions