The foam is eye opening, however the USA sees 20 billion miles put on motorcycles each year
and within that, many millions of bikes that have run Rotella sure don't have a problem. Haven't seen a Rotella related engine failure in a motorcycle on this forum. With that said, I don't use it at this point but have successfully used it in the past in everything from a 45 year old air cooled UJM (XS1100) to an ST1300 and my current ZRX1200.
The problem with this is reliance on self-reporting which is often unreliable. If someone thinks Rotella is a great oil, they're less likely to consider it a culprit when something goes wrong or something is misperceived as being normal.
There was a drag bike team that was changing bearings every few races on T6 and thought nothing of it. They figured it was normal to go through bearings at that high power level and abuse so they never considered it an issue until they tried a more appropriate race oil. That came about after someone ate the cost of a UOA for him and found over 300 ppm Al. Not only did they find power, the bearings looked good as new after three races with <40 ppm Al in UOA. After a full season of racing, the bearings were still in great shape.
While not a motorcycle application, an engine builder near me was having trouble with valvetrain wear in his high rpm LS builds with solid roller cams. It was particularly harsh on the rockers and pushrods. He was using Rotella or Delvac 15W-40 (whichever was cheaper or available) which he swore was great oil. It's definitely not cut out for 8,000 rpm and >700 lbs spring pressure. He couldn't get 10 WOT hits out of an engine without chewing a pushrod. The bearings, while not destroyed, were less than stellar. For months, he blamed everything but the oil, convinced the oil was great and thus couldn't be the problem. He changed parts suppliers twice, damaged 20+ engines on the dyno, trying to make the problem stop. It finally did when he switched to Driven LS30 with no valvetrain failures since.
I've seen several posts on social media and elsewhere of people complaining about clutch chatter. They mention using Rotella but never consider it the reason. They blame the clutch, the design, the OEM, anything but the oil. "Well, I got good oil in it so that can't be the problem." Bias is blinding. I stick with the science.
