This would depend on what type of oil you will be using for your premix. The oil base stock is either petroleum, semi-synthetic or synthetic oil and is mixed with gas at a ratio ranging from 16:1 (petroleum) to as high as 100:1 (synthetic). My 2 stroke I have is a 2001 Kawasaki KDX200 that I run Yamalube 2R at 36:1 with no problems. Although synthetics say you can mix them at 100:1 I would not, that seems way too lean to me.
50:1 ratio
on the cowl of my 1993 DT2 suzuki it states 100 to 1 mix.
50:1
32:1
50:1
20:1
if it is not oil injected rule of thumb is 50 to 1 ratio.
I was told to use a 32 to 1 mix by a bike mechanic
it depends really i have the same bike and i do 40:1 ratio that's 16oz to every 5gal of gas
i use 927 mixing oil and i put 4 ounces to the gallon. : )
There will be oil in the water on a 1997 RM125 if the head gasket is leaking. It allows oil and water to freely mix across the cylinder head and engine block.
Premix (mix oil and petrol at a certain ratio) Contact you local Yamaha dealer for the best mix.