800 miles on my 2012 Multistrada with no issue and then noted a slow leak in the rear tire, will lose 10 lbs of pressure overnight or after riding 4 hrs. No signs of a puncture, I do notice it's hard to put air in through the valve stem now. Is it possible the valve stem is defective and leaking, or am I missing a small puncture? Should I put ride-on in it, replace the valve stem, or should I take it in? I don't have the skills or interest in taking the tire off the rim myself.