Hi!
i have used the gro oil and other 10-40 oils and i feel that when its new, gear changing is smooth and almost no sound.. but when it warms up and after a few days it becomes like its been there for years!
what is the negative of using high viscosity oil? i have read an article that suggests bigger oil for 2stroke trannys for better protection and smoother operation at high temperatures and that makes sence!