This article is from the Ducatis Motorcycles FAQ, by Duke Robillard email@example.com with numerous contributions by others.
Opinions and lore abound on this issue, but the general consensus is that
the key to engine longevity is sticking to frequent oil and filter changes
using quality lubricants, petroleum or synthetic, roughly about every 2500
- 3000 miles. Another frequent tip that seems to be mentioned often is the
concept of varying the load against RPM, and watching the heat, during the
break-in. Vary the load on the engine, but be careful not to lug it. Take
the motor through the full range of RPM's using less than full throttle.
Slowly feeding a load on it now and then to bring it up to 5500-6000 for a
little bit, then backing off again is a good idea, as it helps the rings
break in. These engines in general really want to be running at 3000-3500
rpm at the low end. At any rate, don't let your right wrist get the better
of you -- there will be plenty of time to use full throttle once it's
broken in. Let the bike heat up to full operating temperature and then let
it quietly cool off. Do this often for the first 100 miles or so. Don't
ride in traffic or other situation which will force the bike to idle for
long periods of time -- MAJOR heat buildup!
Another frequent tip from the Net is to ignore the Slick 50.