What engine oil are you using?

[bugeyes]

Time for a service and this time I will do it myself as the price is too steep at the shop.
Wondering what oil people are using, feel this Yamalube semi synth is going bad a bit fast (feel it when shifting).

 

[banjo]

I usually use semi-synthetic but last oil change I used synthetic over the next few rides my gear changes got clunkier and clunkier so much so it felt like I was destroying the gearbox. I changed back to semi synthetic and it is back to normal when I drained the synthetic oil it looked quite dark so I'm not sure it wasn't fake oil.the last time I used synthetic a few years ago on a vfr it did the same thing both the oils both came from the same place. Anyway I will stick to semi synthetic from now on and buy it from a place I trust.