It does not suprise me that Formula+ would quiet things down.
Formula + is basically a GL-3 lube, and very low in additives. The flash point suggests that it is some variety of synthetic
Here is the virgin oil analysis on it if any one is interested. I am glad it's working well for you.
Calcium 169
Phosphorus 230
Boron 210
Sodium - trace
Zinc - none
No other elemental additives.
Vis. within SAE 50 range.
Listed as a GL-1, does test out as a GL-3.
Specific Gravity: 0.857
Pounds per Gallon: 7.14
Viscosity, ASTM D 445,
cSt at 40°C: 168.04
cSt at 100°C: 20.10
Viscosity Index, ASTM D 2270: 139
Brookfield Viscosity, ASTM D 2983,
Flash Point, ASTM D 92, °F (°C): 507 (264)
Pour Point, ASTM D 97, °F (°C): -60 (-51)
Analysis done by Blackstone Laboratories
One interesting point is Harley claims it has a pour point of -60 Fahrenheit.
I put a quart in my freezer for about a hour and it turned into a milky brown goop.