Excuse the stupidity. I just rebuilt my '78 kz650 (air cooled inline 4) and the guy that helped me put her back together told me to break her in with Shell Rotella Multigrade 15w40. I've never used the stuff before so I don't really know the effects on the engine for the long term. I do know that the transmission seems a little clunky, and the engine thins out the oil more then the Castrol GTX or Mobile 1 that I've used in my other bikes. (A shot of Lucas oil helped drastically) The Rotella is also nosier in the top end. I actually pulled the cams after breakin to make sure the shims where correct. I put about 3,000 miles on my bike a month (5,200 miles since I put her back together, working on the third oil change) so I can't afford to use expensive oil, but I would like to know what would be the best oil to use in my conditions with my bike. I live on the Gulf Coast so it's hot; typically mid 90s with 60% to 70% humidity. Most rides are over 30 miles usually running in the 4500 to 5k RPM range. I've used Mobile 1 Synthetic in my cars for years with never a major engine problem. (we have had cars with 200k-500k miles) I've used Castrol GTX or Mobile 1 redcap in the bikes, but this bike is an althogether diffrent beast from my Wing, Vulcans, and Viragos. Just doesn't seem to be getting the protection it needs. Any help is welcome, the more I read the more confused I am.
