Main difference will be price and longevity.
Mineral base is cheaper, synthetic base lasts longer before it breaks down. With 5 or 6,000 mile change intervals, this won't matter. Synthetic is for vehicles with 10 or 12,000 - mile plus change intervals.
Synthetic, semi-synthetic or mineral will all mix OK, despite ill-informed advice you may find to the contrary
The main thing is the quality of the additive package. Detergents, anti-friction agents etc. Any reputable brand will have a good formulation. Look for API SL classification.
As your 1150 has a dry clutch, like most cars and a few other bikes, you do not need a motorcycle grade of oil (with a wet clutch, you would need JASO MA or MA2 grade).
So, any API SL (you could use SF, SG or SH as these grades were originally specified, but they are now obsolete) reputable brand of automobile oil. Over to you as I am not familiar with US brands.
Personally, I use Valvoline VR1.
Hope this helps. You can now expect much mockery from the other denizens of this forum, for daring to ask about oil. Enjoy
An excellent reply....clear , concise and devoid of mockery... the issue was obviously keeping the OP up at night
BTW 10/40 semi synthetic will be fine as well ...although if its using a bit of oil 20/50 may be worth sticking with 
Main difference will be price and longevity.
Mineral base is cheaper, synthetic base lasts longer before it breaks down. With 5 or 6,000 mile change intervals, this won't matter. Synthetic is for vehicles with 10 or 12,000 - mile plus change intervals.
Synthetic, semi-synthetic or mineral will all mix OK, despite ill-informed advice you may find to the contrary
The main thing is the quality of the additive package. Detergents, anti-friction agents etc. Any reputable brand will have a good formulation. Look for API SL classification.
As your 1150 has a dry clutch, like most cars and a few other bikes, you do not need a motorcycle grade of oil (with a wet clutch, you would need JASO MA or MA2 grade).
So, any API SL (you could use SF, SG or SH as these grades were originally specified, but they are now obsolete) reputable brand of automobile oil. Over to you as I am not familiar with US brands.
Personally, I use Valvoline VR1.
Hope this helps. You can now expect much mockery from the other denizens of this forum, for daring to ask about oil. Enjoy
.
Reckons that as it uses a bit it will get replaced with top ups eventually 
Least he still owns it Alaska to Patagonia! Just found your Facebook page
Have a great trip, looks like you're about ready for an oil change and a service at over 5,000 miles.
It's about 10 years since I was in SF, but I rented a little BMW from these guys www.dubbelju.com and found them helpful. Perhaps they would service your bike before you head south into bandit country?
Happy trails, I'll be following you on FB!
