Alfa oil?

[Mr Gazza]

Due an oil change on the ol' air cooled 900.
I usually choose an oil for a particular engine, and stick to it. I use Castrol Power1 Racing 10w-40 fully synth in the Monster... Always have done.

During my Alfa ownership I was lambasted by various enthusiasts about the virtues of Petronas lubricants, particularly Selinia 20K, which boasts the ability to perform properly for up to 20,000km and is rated (by Alfa people) as a far superior oil. They reckon nothing less will do in an Alfa.
This is in liquid cooled car engines of course. My Monster is a slightly different kettle of worms.
I have steered clear of "ordinary" car oils in the past, but the main reason for using a motorcycle specific oil (like the Castrol) is that they are suitable for wet clutches, which most car oils are certainly not!
But I have a dry clutch, so I don't need to worry about that aspect.
Just wondering about changing (permanently) to Selinia 20K 10w-40 semi synth... It's not that different in price to the Castrol.

[Flip]

I’m no expert but I always thought another property of motorcycle specific oils is a greater shear resistance compared to that of car oils.

In almost all cases a motorcycle oil has to lubricate the gear box (as well as the engine) and is constantly getting ‘chopped up’ in there which causes oil to lose its viscousity far quicker (one of the reasons motorcycles have shorter oil change schedules) and so motorcycle oil has anti shear additives to help combat the effect of running through all those gears.

[Darren69]

Yep, thats why car oils aren't so good in bike engines, the gearbox,

[Darren69]

They also do some techy stuff with it so if you have a wet clutch it won't slip like bejesus too. I was recommended by my local Duke expert to use Motul 300V for the S4 and 748 DQ motors. Thats like £15 a llitre but the one below that they do should be ok for the aircooled 2v motors and a bit cheaper too. I think its the same base but semi synthetic added and its not bright green!