Originally Posted by Arrybash

A motorcycle engine gives oil a much harder time than oil in a car engine. This is because of the wet clutch and gearbox. As stated earlier modern bikes need the JASO spec oil this is the link which tells you all about it http://www.jalos.or.jp/onfile/pdf/4T_EV0604.pdf I always use a decent motorcycle oil in my Tiger. Chris

Thanks for posting the JASO link.......very informative. One of the things JASO oil addresses besides wet clutch issues is oil foaming in the gearbox. All those tranny gears spooled up to so many thousand RPM will aireate and foam diesel and automotive oils. This has drastic effects on lubing ability. Motorcycle oils use an additive package heavey in anti foam agents, something automotive and diesel oils dont need. I use a full synthetic motorcycle oil in my Tiger ($12.00 a qt) and change it around 6000 miles. Any true full synthetic oil can easily go that change interval.