| Valve gear is the harshest environment in the engine for oil, problems with marginal lubrication will show up first here.
There seems to be an assumption that thicker oil (50)offers better protection than 40.
A mineral oil of 40 or 50 weight will have a film strength of about 5/600 PSI.
A proper synthetic either 40 or 50 will have a film strength of approx 3000 psi and better "cling" which is good for rarely used bikes.
A good synthetic will have much better flow at very cold temperatures.
By the by, just heard from John Hackets that my bike (748)did not need any rockers at its 2 year service.
It runs on Motul 300 V @1500 mile changes or Amsoil @3000 miles changes. These are both ester based oils with a 3000 psi film strength! |