Penrite Oils for Big Blocks

Pete, I notice Penrite have differentiated their 10W60 oils: there is 10 tenths and there is MC-4ST 10W60, which is the current buy for our big blocks?

I need to order a 20 litre drum so I can give the old girl some love juice, soon as I reach a new town...

I just use the Ten Tenths. I tend to think 'Motorcycle' specific oils are a bit of a furphy.

I've heard all sorts of arguments about the non MC specific oils having friction modifiers that will make clutches slip in wet clutch systems. Well I've been running the same oil in the FJ900 and it's towing a sodding great sidecar. Does the clutch slip? Not so far.

I do strongly advise against a true FM specified oil in Guzzis as the friction modifiers used, (Note tense!) to cause bore glazing. Whether they still would I know not but I'm not going to experiment to find out!

Thanks Pete, appreciated!