There ws quite a lot such threads recently. Oilman wil recommend either Silkolene something something which I don't know as it is not avalible here, or Motul 300V series - for summer I would reccomend 300V Competition (15W50), but if you use it on the track you can even go for 300V Le Mans (20W60). For lighter use on road and winter 300V Chrono 10W40 is a great option.