I just completed a 12,000 mile trip on an 05 R1200GS around the US and Canada in 62 days. The bike ran flawlessly for most of the trip. At the completion of each day, I would check both the tire pressure and the oil. I'd put the bike on the centerstand and check the oil giving it 5 or 10 minutes to settle while hot and then add, if necessary, enough oil to maintain a three quaters level in the sight glass. With the coefieceint of expansion of 20W50 BMW oil, this would drop the oil level to aproximately 1/3rd the sight glass when cold. The oil level is always meticulously maintained on my bike. The bike was never beat or top ended. I got 12,000 miles on the original Metzler tourance tires. OK, now for the problem. At 15,700 miles I felt the bike surge while riding towards Big Bend National park in Texas. At first I thought I had been buffeted by a wind gust. Then I heard the knocking. Very similar to loud rockers or valves. I stopped the bike, had a smoke and checked the oil. The oil level was in the 3/4 range in the sight glass. As i was in the middle of nowhere with only Buzzards and Rattlesnakes to keep me company, I decided to proceed to the next town of any size which was Fort Stockton, Texas. I found that the knocking would subside if I kept the bike at 60 mph at approx 3000 rpms. Any load placed on the engine either by throttle or say going up a hill it would return. I wound up towing the bike to San Antonio, Texas. Alamo BMW of course check the valves (O.K.) and replaced the cam tensioner. This did nothing to quiet the knock. The bike is under warranty and they told me they would put a new engine in. It has yet to be determined what failed. The bike was serviced at 6,000 and 12,000 miles by BMW in Greenville, South Carolina and Missoula, Montana respectively. There was no indication until it happened such as a rise in oil temperture prior to failure. I have heard rumors that being a first generation engine, when the bike reaches the 15 to 20 thousand mile range, blockage causes insuficient oil to the bearings and of course they fail. My question to you is this. Have you heard of this problem occuring to other members. I have yet to confront BMW until all the facts are in. A new engine is fine however will I wind up telling a dealer every 15,000 miles or so "Check the oil and, oh yeah, replace the engine". Thanks Smitty