Found this on the Halford website.
I know it is 10/40 not 10/50 but BMW manual says that 10/40 is okay up to 30 deg C ambient rather than 10/50 which is good for all temperature ranges. But how often does it get to 30 deg C? I used 10/40 part Synth in my Blackbird all year round and it was fine. In fact the Halford own fully Synth exceeds all the various specs that the Castrol does. That might be a worthwhile choice.
I know it is 10/40 not 10/50 but BMW manual says that 10/40 is okay up to 30 deg C ambient rather than 10/50 which is good for all temperature ranges. But how often does it get to 30 deg C? I used 10/40 part Synth in my Blackbird all year round and it was fine. In fact the Halford own fully Synth exceeds all the various specs that the Castrol does. That might be a worthwhile choice.
and this er 10w - 50 is like gold dust as I had to goto three stores before finding it. Bike had got 7k on it and it just took 500ml to get her to mid level on the glass. Called the dealer and this is "normal". Probably will carry a little bottle since no petrol stations seem to stock the stuff.



