aah, the old 'friction-modified' wives tale pops up yet again.
Castrol made a 'friction modified' oil about 20 or 30 years ago

, when 'Oils ain't oils Sol ' ......and yes, that *particular* brand of Castrol automotive oil (Castrol GTX) was not recommended for use in motors with a wet clutch. It even said so on the side of the bottle ...
You won't find that message on modern-day motor oils. You can use just about any SE-rated engine oil in a motorcycle with a wet clutch without clutch slippage problems. One of the boys up here has run Shell Rimula X in his GTR for years, and its a diesel motor oil !! It is also one of the highest-quality mineral oils that money can buy - and he swears by it.
Check the manufacturers specs for the *right* oil for your bike motor. The rating of the oil and the viscosity are the only important things. And if you are still unsure, check the fine print on the label - 99 times out of 100, it will state that the oil is suitable for use in motorcycle engines .......
......the only thing that changes is the price - Put a picture of a motorcycle or a boat on the bottle, and its *instantly* twice as expensive !!!
