Make sure to check out the clutch basket, see if it rolls when put in gear. They aren't cheap so finding one that has a good clutch basket is a money savor. That era of RM's are really bad with the clutch baskets, mine ('98) rolls, but not so much I need to replace it. Very good bike though, I love mine.
rm125 from what im reading are known for low end issues... as well as the clutch basket as mentioned. Most people planning on riding the bike hard from what i have read change the clutch basket out to an aftermarket basket which solves the problem with it rolling in gear.
My 97 rm125 flys in the upper and mid range however the low end sucks... from what ive read there isnt much of a fix to this other then getting a 250
other complaints is that my 97125 feels like its in a 250 frame.... the bike feels huge and heavy to me.. looking at it you would swear you were looking at a 250. also the front shock design just dosent seem forgiving enough, however I must say it does get over damn near anything I put in front of it if im already moving... from a stand still getting up a short steep embankment can sometimes be difficult.
Another thing i dont like is the 25 dollar spark plug you should use that is suggested in the suzuki manual.... I have heard of others using a cheaper plug, however if you want to play it safe then plugs are gonna cost you somewhere in the range fo 25 bucks.
Overall I would give my 125 a great review.. from an experienced riders point of view.. if you like a clutchy , high end of the powerband type of ride I would say the bike is for you. Im just a trail rider who needs instant power rather then speed. The more i read my own words the more it seems I need a 250 :)
I have a 99 rm 125 it's a rocket I can pull 250fs on the straights, but it has a $1000 mod motor and runs on u2 it goes like hell though. The trade off is that it eats pistons and rings often. No big bore either straight up 125 it's a blast. :laugh: