I know that this topic has been written, hashed, fought over, and opinionated thousands of times on this forum and others across the net. This thread isn't to see what type of oil is the best oil to use in our bikes. We all know, that according to the topics on this forum under "oil", there are 10-20 "oils with great results". My question is from a different angle; does anyone have any experience with an engine failure that can directly be attributed to the engine oil? Obviously there are stories of engines melting down but then the truth comes out that the owner changed the oil perhaps two years ago? Or was it three? And it was one quart low at that! I'm not talking about the folks that do nothing in the form of maintanance with their bikes. I'm looking for stories of people that do great mainanance on their bikes; change the oil every two or three rides, change the filter very often, check the oil levels daily, etc. But then the engine does fail or prematurely wear out because of the type of oil that they put in the crank case. The reason I ask this is I've got a 1995 XR250R that has approximately 1000 hours on the bike. If during those 1000 hours the bike averaged 20 miles per hour, thats 20,000 miles! Most of those miles have been done by a teenager that raps the engine too fast, rides it during the heat of the day in the desert, loves to hill climb getting the engine hot, etc. The only oil this bike has ever tasted is Pennzoil 20W-50. However, one of the things that we do is change the oil every two to three rides. Change the filter every oil change. And we check the levels daily. We never have to add oil between changes and the bike still runs great. In fact, this bike will probably be passed on to the sister when she is tall enough to touch the ground. There are studies that show that certain oils break down faster than others, cause clutch slippage, etc. But are there oils that can be documented to cause engine failures in motorcycles even with great maintanance schedules? Oils regardless of their makeup? I.E. synthetic, blends, dino, recycled, etc? When we change the oil on a regular basis, every two or three rides like most seem to do on this forum. Perhaps there are many oils that will work with "great results". From the Mobil 1 to regular Pennzoil. I don't have an axe to grind nor a point to make. I'm just curious. I've never had an engine fail nor wear out because of the kind of oil that I used. Thanks folks.