Proper Break In
The goal is to let the rings wear down some to conform to the cylinder. So using petroleum (mineral) oil, not too thick, is good and then after break in use fully synthetic oil or semi-synthetic to not smoke much and get good wear protection. These are oils that are "petroleum", without synthetic oil, and my recommended ratios of use for break-in without prolonged hi RPM runs; Amalie SynPlus Oil 20W-20 (30:1), Bel-Ray Mineral 2-Stroke Oil (34:1), Yamalube 2R (35:1), Amsoil Interceptor (30:1), Golden Spectro (35:1).
Good semi-synthetic oils to consider after break-in and their 10,000-12,000 RPM ratios: Motul 510 2T (31:1, 27:1), Maxima Premium 2 (37:1, 33:1), Motul 710 2T (39:1, 35:1), Maxima Castor 927 (50:1, 43:1)
Full synthetic oils: Red Line AllSport (62:1, 55:1), Bel-Ray MC-1 (61:1, 52:1), Maxima Super M (45:1, 40:1), Motul 800 Off Road (56:1, 49:1). To read more about the details of these oils and what other oils are available just go to www.dragonfly75.com/moto/oil.html
ps - and all ratios are based upon my computer program that calculates ratios based on oil viscosity at estimated upper cylinder temp, type engine cooling, and max RPM. I prefer semi-synthetic oils because the non-synthetic oils have some properties that the synthetic oils don't have. Of course if you are after the most smokeless oil possible then buy one that is 100% synthetic.
Proper break in is to help the rings wear down in conformity to the cylinder for better compression. My general suggestion is just to 1) Let it idle until engine gets hot, then let it cool down, 2) ride it easy for 15 minutes then let it cool down, 3) ride it easy but occassionally ride it WOT for short bursts, not more than 15 seconds. Those WOT bursts are when the most cylinder pressure is generated which puts maximum outward pressure on the rings so they can seat good. You can continue to use up the gas/oil mix in the tank if you don't ride hard, and then switch to a semi-synthetic or full synthetic oil at the ratios I recommend above.