You will get many responses based on opinion, the actual reccomendation is 5-30 but imo this is to thin. I use Silkolyne 10/50W, my reasoning is it won't cause much drag when cold and the 50 weight offers good protection when hot. Not had any problems with this.

Second that article, read that before is a good read.

The author of it (Oilman, AKA Opieoils) you will get a 10% discount as well for being a member on here if buying from him.

Martin