K. For the price of syn 3 you can get a premium oil,not that re-badged citgo crap. However no bikes blew up with any approved oil so you just gotta ask yourself what are you comfortable with. I use a 5w-50 for spring and fall and a straight 50 in the summer. Amsoil,red-line,mobil 1 gold cap and royal purple are all group 4 or better basestocks which means they are a true synthetic. Castrol syntec,mobil 1 tri-syn,penzoil platinum and h-d syn 3 are all group 3 which are a highly refined conventional. So if you choose from the first 4 options you are getting what your paying for. The other 4 aren't real synthetic and the syn 3 is actually a group 2(conventional),group 3 ( refined conventional) and group 4(synthetic) all mixed together. So I shy away from it simply be wise there are better products for the same money.
And because our bikes aren't a shared sump we do not need the expensive v-twin oils with the JASO spec. That spec is for *** bikes. The v-twin oils are good products but not worth the money. If you live in a warm climate any 20w-50 changed at 3000 miles will be fine. Synthetics last longer and resist shearing for longer than conventional. They also dissipate heat better. In the end you have to be comfortable with your choice.
I personally hate anything mobil but tha doesn't mean they don't make good oil. Red-line has a 3 product bike package that I personally really like. The shock proof heavy in the tranny is a must have. It comes with oil for primary and 20-50 for the motor. If you can find that package buy it. Amsoil is also top notch but personally I would use the 75w-90 gear oil in my tranny. They shift better and easier to find neutral.
Honestly though these bikes have been running for 100 years with regular oil so it really comes down to your maintenance schedule. New oil protects better than used oil.