I have seen questions posted on high altitude performance so I thought I would post what I have experienced. I have recently returned from the s/w Colorado Rockies and I climbed over Ophir Pass elevation 11,789' on a 2005 TW200. It performed well but of course had noticeable power loss. Technical sections are fun on a TW because it takes some skill to negotiate extremely rough and steep sections at these altitudes because at times you have to feather the clutch and peg the throttle to stay in the power band. The bike is factory jetted.