No truth to that at all. The top end oiling system is the same today as it's always been. A tried and true system sense the very first V-Twin. They have an oil tube that runs straight up from the lower galley right off the oil pump to each head which pressures the crank as well as lines to other parts. The piston get oil from sling and spray off the throw and that is not effected by angle so...nope. No truth as far as I know. Now they have changed the crankcase venting system a bit to stop oil travel up that tube during wheelies and steep high RPM climbs...but that's all. Now with that said, there is a possibility of the pump intake pulling air if the angle..or wheelie is more then about 58 degrees. Making sure your oil is at the top of the stick usually is enough to solve that though. Those that worry about that can install a pressure gauge and if they see it start to drop...they can back off the wheely a bit.
