Hi,
I have been using fully syn engine oil for the past 7 yrs of
riding.
Been using 10w40 for my Super 4 and 20w50 for my Blackbird.
I strongly agree that a higher grade of engine oil is needed for
extremely high temp engine ie. Blackbird.
i tried using 10w40 on blackbird to hit higher mileage but changed
to 20w50 after 1000km because of the stronger heat coming.
however, 2A bikes can still use 10w40 because of the 'lower' or
acceptable emitted heat. 20w50 is more of a over-kill.
Speedjpop