I've had good luck with Mobil 1 products in all my vehicles. Both types of bike oil test very high in any type of comparison test. My buddy's '07 Wide Glide has over 60,000 trouble-free miles using the 20/50 Mobil 1 bike oil. To me, the only reason NOT to use synthetic (other than the ever-escalating price) is if you enjoy oi changes enough to do twice as many.