97 rm 125 clutch and idle

Try to set free play to almost nothing to pull the clutch in more,and try another type
or oil,like pennsoil,and last choice buy a new clutch basket which is because the old one is probably notched.
overbore.

Is the clutch "grabbing" or "slipping" at low rpm's. I'll assume you mean grab, and you have the clutch lever pulled in, and this is why you tightened the cable. First get a book, you need one. Second don't ride the bike if you know that the oil level is over filled. I know when people get a new bike, the first thing they want to do is go and ride the piss out of it (this is normal). Really the first thing you need to do is get a book/manual and read it, then check the bike over, then ride the piss out of it. Just one of the things that could cause the problems you are describing, is water in the oil from a leaking/worn water pump, is the oil in good shape? Get a book (not trying to be rude). bjawes