Yamaha Venture users' forum

...with practical experience counseled against synthetic due to the wet clutch... too slippery, making slipping possible. So of course I've gone and used Rotella synthetic and Bosch filters: both the highest rated when last I checked. Synthetic in my 97 LeSabre; conventional in the oil-guzzling 03 Expedition (waste of money there). Filters are more important, oils being generally all so advanced now they work well for 5-7 thousand miles. Some have done good tests cutting open & checking filters. Fram had notoriously poor innards; guy did a thorough check but Ford's lawyers threatened him so he took down the site. Think I had copied it before he gave in, somewhere into my computer.