I'm changing my clutch plates with new Kevlar friction pads. My manual says use SAE 15W50 oil ... I'd like to return the 20W50 yamalube which I purchased. I believe that's Conventional because of the price(18 bucks for a gallon) and use some inexpensive Sythnetic oil with my new K&N filter where I could buy at the local walmart or Auto store in California . I had a lot of sludge and carbon pieces from my old clutch. have you guys used any inexpensive "car" oil on these bikes? what do you think? thank you for your information/feedback in advance