Ok - so I have a 2010 XLN 1200 Sportster that was bough used in 2012 with 1800 miles. Did an oil change and changed rear tire last Summer with about 5,000 miles and adjusted primary chain. Mostly highway miles driven. Getting ready for a MC Harley sponsored ride this summer and 6500 miles and noticed primary chain loose again. Also noted the primary oil was low. Adjusted and added half a quart of oil. 750 miles later (after the ride) two days, drained primary oil, only 1/3 quart and brownish in color again. Added over a quart of oil and drove another 300 miles and took to dealer. They noted that the primary chain is completely stretched, adjuster & shoe needs replacement, noted only 1/3 quart of primary oil & brownish in color. No leaks, no extra oil in engine. Recommending to do a complete tear down to see what is happening and where the primary oil is going. Big $'s for something their lead mechanic has never seen nor the Harley Tech support people can help with. Has anyone seen this before and what is the cause.