I know that this may be a controversial subject, but for breaking in the engine, I'd look for an older grade of oil in the API ratings, such as SL or before..
The most recent rating is SM, which has changed the additive package to improve catalytic converter life on cars.
In the SM rated oils, they have lowered the levels of ZDDP(a zinc compound) and phosphorous, both of which are friction reducing agents, that were present in higher quantities in the pre-SM formulations of oils.
There is still a fairly good quantity of SL rated oils out there on the shelves, but you may have to look a little harder to find it.
It's worth it, because these ZDDP and phosphorous additives in the older oils are better at protecting cam faces and solid lifters, which we have in our Bullet engines. Most new cars have hydraulic lifters which aren't really affected by this change. But, classic car owners and classic bike owners have noticed increased wear during break-in periods with the new SM oils, so I'd look for some of the SL or earlier type oils, and see if you can find some.
I use straight 40wt SL oil in my Bullet during the summers. I only use multi-wt oils during the winter, and I really don't ride much in winter anyway.
The straight 40wt is okay as long as the temps don't drop below 60*F at night, so that the oil doesn't get too thick for starting up in the morning. In my area, it is always over 60*F in the summer, even at night, so I'm okay with that wt oil.
I do concur that it may be better to use multi-wt oils in the beginning, so that the engine isn't having any difficulty in moving the cold oil around when it's cold.
But try to find some pre-SM grade oil in the API rating listed on the bottle.
It's funny, but usually the cheapest "house brand" oils are still the SL type, probably because the oil companies had alot of it produced, and now the rating calls for a different additive package, so they probably sold all the SL rated oil off to the places like Auto Zone for their "house brand" oil.