2012 road glide custom with 103". been chasing some weird harmonic clattering right around 2800-3200 rpm and after taking apart entire primary, cam plate, and rockers have now started looking to validate the engine is running right. i had the bike tuned at RC cycles back in 2015 and it has been running great since then. this sound started about 9 months ago. all mechanical components so far are checking out. tuner module is TTS

i ran datamaster logging runs for spark data and O2 data. the spark data looked good and i could not find any knock events or anywhere where the spark was being retarded.

i did see some interesting readings for the O2 sensors. when the bike starts they start high as expected then drop down but the average voltage is around 1700mV. i plotted the data and it looks like the range of voltage seen during my logging runs is between 800mV and 1900mV. i am having a hard time believing both O2 sensors went bad. i have been reading that the normal voltages should be between 600mV and 1200mV.

other weird things is the O2 sensors will have big shifts from one frame to the next, going from 1700mV to 900mV, then back. this also will happen with one O2 sensor dropping to 900mV while the other one stays high at 1700mV. when this happens there is no big change happening with MAP, TPS, or RPM. this seems to be happening at 0mph while i am at a stop light as well as when i am cruising at 80mph and 3k RPM. for most of the time the mV seem to be on the high end around 1700mV.

i validated the sensor wires aren't broken, the connectors are good, and the sensors are in the right configuration. bike runs like a champ and plug color is good.

thoughts?

 

O2 reading are design to go high and low like your talking. That is why it's nicknamed a switching sensor.

 

Steve - you beat me to it! How the heck are you?

 

Same old same old, just a different day and still getting older.