There's a small bolt on the side cover that you remove. Then you add oil until it begins to run out of that hole. Put the bolt back in and you're done.
My question is how much oil do you put in and what type? I have an 89 CR125. I've been told between 650 to 700ml of oil and I have heard of using ATF transmission fluid, 80 weight gear oil and most recently someone told me that they've had good success and use it all the time which is Shell Rotella 15W40. So which oil do I use. Being that it is for the clutch plates using ATF transmission fluid makes a lot of sense to me but at the same time I would never consider putting 80 weight oil in it nor would I think using 15W40 engine oil that's meant for a diesel engine. So what is best or would be good for clutches? So that's why I'm asking