I was running 10w-40 Amsoil exclusively and pretty much the only time I ever experienced clutch shudder was if I tried to take off when the engine was cold, and very rarely when it was warmed up. Then I had the incident in August with my fuel manager that caused my fuel injectors to pump raw fuel through my engine and contaminated my oil. Because I like to change my oil and filter late in the fall just before I put the bike up for winter, I decided to use a less expensive conventional oil (Rotella 15w-40) to replace the contaminated oil until I was ready to put in the Amsoil for the winter. Since I've been running the Rotella I've noticed I get shudder almost all the time now, even when it's hot. The only way I can avoid it is by letting the clutch lever out veeeerrryyyy slowly and keeping the RPMs at, or just above idle when I take off. Trying to take off any other way results in bucking like a bronco. I'm wondering if when I drain this oil and go back to the Amsoil if I shouldn't go with the 20W-50 instead of the 10w-40? Since the concensus seems to be that it's an oiling issue that causes the shudder, the thicker oil SHOULD cling better to the clutch surfaces and therefore I SHOULD have less shudder. Of course, this is only a theory of mine. Whether or not it will actually work, who knows? Have any of you guys experienced less clutch shudder by moving up to a thicker oil?