Review on NGK Iridium IX DCPR7EIX Spark Plugs: Harley Davidson Twin Cam (Pair) - 1999-2016 Model Years by Gary Duncan

These spark plugs banged on the seat for 1000 miles then my bike ran lean and started having spark knock issues. I measured the resistance and it is 4.3k ohms, standard candles measure 12.4k ohms. I put the original spark plugs back in and the spark knock and engine codes are gone. I have a 2004 HD fxstdi with an open loop system and these spark plugs were causing problems as the change in resistance after detonation is measured by the computer and causes it to tilt and go into safe mode. Not worth the extra money, stick with standard resistance forks!