I use Rotella T6 full synthetic. It's 5W40 and has a JASO MA rating (meaning it is safe for motorcycles with wet clutches. Readily available at Walmart at $21 a gallon or less. Aprilia puts 5W40 full synthetic in the RSV and Tuono at the factory. My Vespa came with it in there too (the Italian brand AGIP, not Rotella T6). Lots of good synthetic oils out there though. I ride hard and we have very hot summers, so I need all the protection I can get. The advantages of synthetics you always hear is that they resist breakdown to heat better and last longer. Mobil, Shell, Castrol, Royal Purple, Amsoil, all put out synthetics for motorcycles. I don't know about the Kawa synthetic, but I'm sure it's good stuff too. I do my own oil changes obviously. I do use the OEM oil filters cause I get them as cheap or cheaper than Wix, Purolator, K&N, etc. when my local Kawa offers 50% discounts on parts. The move is toward synthetics. My Prius and Fiat both came with full synthetic oil. In the case of the Prius, the first oil change is at 10,000 miles. With a motorcycle though from what I've read, it's the filter that gives out first and may even become clogged early on, hence the early oil change. With the hard break-in the oil and filter get changed at 50 miles or less. That's what I did and put in the Rotella T6 at that time. Who know though? So much speculation except for the better characterisitics of synthetic compared to dino oil. That's not in dispute.