Sometimes called the Italian Tune-up. You know the idea - thrash the pants off a car or bike for a few miles and it goes better. What I want to know is - why?
Recently I had occasion to ride the bike a lot harder than normal, and ended up doing about 10 miles flat-out with the throttle to the stop. Since then, the bike has felt like it has a new engine. It's much livelier, and the same throttle position seems to be about 10 mph faster on my ride to work. It revs out easier and has noticeably more power for overtaking.
I know this happens, but I'd like to know why it happens. What changes in the engine happen with harder use that make it more efficient? It certainly isn't carbon build-up because I had the head off last year and the engine was clean as a new pin inside. Not the sparking plug, because a new plug at service time doesn't have this effect.
What's going on, folks? Anyone have any idea?
(My guess, for what it's worth - the extra heat and piston friction slightly deglazes the bores and/or rings and allows better compression. But that's a shot in the dark, and I really don't know.)