In stock form, it was my understanding from factory guys that the EVO engine was designed to 100k trouble free, as the TC was supposed to go about 200k in stock form. The testing is something else on these engines. There are weak points though that come from the factory, often those weak points are exacerbated by aftermarket accessories. I replaced the cases on a stock EVO ( except air cleaner and jetting ) with 88K on it. Everything else was serviceable and the bike ran fine. The weak point on the EVO cases was the right behind the lifter blocks, which in this place cracked, however the bike still ran fine. The cam tensioners are a funny thing. I have seen them go 30k plus and are fine. I have seen them go within a few thousand miles. I have always theorize that the cam tensioner wear was directly proportional to how the person rides the bike. Constant revving and hard launches place extra or more constant pressure on the cam chain tensioner. As for the flywheels, for me, that is an inherently bad design. Keyed on one side, driven off one side. So I rev the snot out of my bike, I drop the clutch while all that weight is spinning. The EVO flywheels are light as hell compared to the older bikes. All the momentum is now asked to come to almost a stop. The left flywheel is now taking most of that stoppage to transfer the torque to the sprocket to the primary chain on to the clutch and mainshaft to the belt or chain to the wheel, however the right side of the flywheel is still hanging out there on a press fit and kinda wants to keep going. I use to tell people, weld them up, stop doing what your doing, or be prepared for me to rebuild or replace them.