What about the break in period up to 1500 miles following the initial 600 mile break in? How important is it?
Every Ducati engine is run-in for ten minutes or more on the dyno using a prescribed rpm and temperature sequence. The piston rings seal is mostly complete after this initial test run. The follow-up part of the break-in that you read in your Owners Manual has little to do with piston ring sealing. It’s meant to accommodate the time it takes for normal wear to occur to thousands of mating parts.
The initial break-in period is actually the final finishing step in manufacturing an engine. At the factory, Ducati hones the cylinder walls to a fine finish, grinds cams to accurate, smooth profiles, and makes connecting rod journals to high standards of roundness and accuracy. But, metal surfaces are still microscopically rough, consisting of tiny peaks and valleys. When you start a new engine, these surfaces must slide over each other and wherever the peaks stick up higher than the local oil film thickness, metal hits metal, welds momentarily from the intense local pressure, and then tears away. The oil flushes away these bits of metal, and the oil filter removes them from circulation.
This process works quickly at first, then more slowly as break-in proceeds. Once the high spots are knocked off or pushed down, the roughness of the surfaces no longer sticks above the oil films. Piston rings have filed themselves into a fine fit to their cylinders. Bearings spin without metal-to-metal contact, on full oil films.
If you decide to ignore Ducati’s recommendation that engine rpm be limited for the break-in period and instead you run at high rpm and heavy throttle, the wear process may generate more heat and metal debris than the lubrication system can handle. Then the result is destruction of contact surfaces in some parts of the engine.
If you use Ducati’s break-in method and gradually build up to higher revs and throttle, the washing action of the oil will keep up with the generation of wear particles, and the surfaces will bed into each other in such a way that the oil film can carry the load.
Finally, the initial period of moderate operation needs to be followed by some hard acceleration and brief trips to the red line. Sustained, high-speed operation is not a good idea because it provides no wash time at low load, during which the oil system can flush away any wear particles.
