Did my 600 mile maintenance at 633 miles. Valves were ever so slightly loose. Pretty easy to do. Everything else looked good. Changed oil, cleaned screen, replace filter. Just a word about changing the filter, the spring that puts tension on the filter is kind of a pain to keep center when putting the filter cap back on. Just a very little dab of grease on the filter where the spring centers, keeps it there until you get the cap is on. Changed gear oil. Nothing unusual, and pretty easy for the do it yourself to do. Not use to working on tiny motors like this, didn't know they could make a timing chain that small! It really is a jewel of a motor though.