This is for my 2007 KTM 950 (SMR). My bike has always consumed oil, and it has been slowly increasing over time. In the past year, I've had spark plugs fail twice due to oil fouling. In past service, I've been able to see a small bit of oil on the top of the valve (looking down the intake). I got what I believe is a confirmation of my leaky stem seals a couple months ago: Doing a bit of mixed-surface riding, a friend riding behind me noticed a big puff of blue smoke when I twisted the throttle after a long slow downhill section during which I was entirely engine braking. My understanding is, engine braking will suck oil through the leaky valve stem seals. When I get back on the throttle, the accumulated oil burns, causing blue smoke for a moment, which is exactly what I got. FYI, I already replaced the balancer shaft seal last year. So, my questions: Can anyone think of any other reason, besides a leaky valve stem seal, that i would have these symptoms? Has anyone ever replaced their valve stem seals? Is there any realistic and safe way to replace these seals without removing the heads, and all the work related to that? FYI, I'm just about to do my 20k miles valve check service. That's why I'm asking this now. Thanks! Edit to say: This work has been completed, and the bike has been running GREAT! Index of thread: Actual work starts Trying to remove valves the lazy way, and failing. Trying again... the right way. Moving to a lower entropy state. Aka, reassembly begins! Engine work finished. Buttoning the rest up. First start!