I generaaly agree with the article by Cold Rider, but perhaps to a lesser extent. I always thought break in for a NEW motorcycle was as much to make sure something wasn't going to fall off, as for the engine itself. This wouldn't apply to a 1550 (assuming bike itself has some miles). I thought my owner's manual on my new suzuki mentioned heat cycle, although not positive. I'm getiing ready to go riding as i type this, but will verify this later today.
The web page Cold Rider posted is right on the mark. Back when I was doing lots of Heavy Duty truck engines Cat, Cunnins, DDA and Navastar all called for loading the engines as described in the web page, With the new materials that are used in piston ring you need cyl. pressure to seat the rings. This doesn't mean that you beat the snot out of it but easy break in is an old wives tale.
Actually, i have followed a variation of this method for the last 20 years, 9 new bikes, 14 cars, plus a few "new engines", hopped up to go faster. I take in easy for a half hour or so, just to make sure it won't blow up, then ride in normal. EXCEPT, I avoid long highway stretchs at a contant speed for a few hundred, plus try to avoid getting it real hot. never had any problems that it didn't think were mechanical error (e.g. a broken head bolt on my stage 2 kit, I think it was overtightened).
However, I would not suugest anybody follow my method.. If you are at all unsure, follow the manufacturer's reccommendations. The only downside is it may have a little less power.
On my AXTELL kit it tells you to heat cycle the engine for the first five minutes of run time. You run it for 30 seconds shut it off until cool. You go through this until you hit the 5 minute mark. It ads like 5 seconds of run time one each of the heat cyclesas you go along. It is a pain in the summer as it takes a long time for the engine to cool completely.
I'll be breaking in my SBC kit this month. It will be 50 degree ambient temps at best during the initial break in rides. Is it ok to break in the motor at these colder temperatures? At 50 degrees ambient my 88 would see 160-170 degrees.
To my knowledge, cooler temps are the best to break in a new engine. The info that I have always been provided is that the oil and cylander walls do not get as hot so the oil does not glaze the walls of the cylander and therefore allows a good clean rub-in of the rings.