Is this a ‘normal’ amount of engine noise for a R16 engine? It is running great but there are no 311 owners around these parts for me to chat with and compare notes. I have worked on many four-bangers (incl. a SPL311) in the past, but that past was decades ago and my auditory baseline for these appears to also be … old

Tune-up, valve adjustment, tightening of whatever needed tightening has been done, no exhaust leaks, etc. I’ve intentionally set the SUs a bit rich to address a lean pop-back condition on very hot days at cruising speed (which has worked fine). That’s the reason for the bit of loping at idle which sits at about 750 RPM. Temp, oil pressure and charge are all good across the operating range - It just seems a bit … louder than I remember.