Hi guys !! I was thinking to switch my engine oil for my yamaha r15v2.0 from semi synthetic to fully synthetic, Motul 300v 15w 50 as it has been crossed 15k...But still confused which one is better ?? the 300v or the 7100 ?? and switching to a fully synthetic oil will cause any harm to my engine ??? as it is not recommended !! And what about the coolant ?? motul motocool is better or is there any other coolant out at the market ?? please do help me with your valuable feedback.