Last Sunday after a 250-mile ride pushed me over the 5,000 mile mark on the oil change, changed out the M1 20w50 Vtwin from my ZRX 1200 and sent in a sample. Replaced it with M1 10w40 4T racing. Ran this oil previous to the 20W50 Vtwin, and got a good result from analysis.
Looking forward to the analysis and will post in the motorcycle section when I get it back on the M1 20w50 Vtwin.
Shift quality remained high with either oil at 5,000 miles. If the oil stays in grade and TBN comes back decent on the 20w50 Vtwin like it did on the 10w40 4T last year, either of those oils is my choice moving forward for extending out to 6,000 miles or more.
Leaning toward the 10w40 4T only because I do feel the engine ran a bit cooler overall in the hot summer temperatures at high elevation compared to the 20w50.