I spent most of the day replacing the ingition system on the Sportster. I’ve been trying to cure the detonation problems caused by my 1200 conversion. Because of the increased compression I’ve been running 93 octane and have taken 2 degrees off of the static timing and still have bad pinging when the engine gets heat saturated.

Thanks to recommendations I picked up a Daytona Twin-Tec 1007 ingition module, a single-fire coil, and new plug wires. The replacement of the existing ignition system went well, with the only real hitch being the connection from the new ignition module to the tach. In the stock Harley configuration there’s a pink wire that runs from the module to the coil to the tach. In the new configuration that’s verboten, so what I did was cut the ring terminal connected to the two pink wires, connect the one running to the tach in to the dedicated tach output wire from the new module and the other to the new coil.

First impressions are favorable. It starts a lot better and the single-fire ignition has made it a lot smoother. I tried beating on it as best I could and it didn’t ping. Next step is to take it down to a dyno tuner and get it dialed in for real.