Drain it and put the right amount back in it, it shoud say on the side cover right near the oil cap
You need the mixture of gas and oil mixture for 2004 YZ 125 in the ratio 1:32.
Yamalube it is ment for the bike.
125ml
No oil filter, the YZ125 is a 2 stroke.
1 quart
82-83 yz 100 holds 600 ml,hope that helps
A good way to tell is change your oil. When a head gasket blows you will have water in your oil or oil in your water system. Check these 2 areas for water and oil.
no its premix but there is 4 stroke oil in the gear box
yz 125 use the same plastics from 1996 to 2001
750ml - 3/4 of a quart
10w30 will be fine
no i have a 2000 yz 125 and can beat a kx 125 blind folded