wikidee

Hello I am Dave this is my first time posting here so please forgive me if I have posted in the wrong section . I am looking for a bit of advice really . I am not a mechanic but can do basic repairs so please bear with me . I recently decided to have a ride on my 2010 ybr 125 cc last time i used it was about 3 years ago so I was going to take it for a MOT so that I could give it to my son to get to work or just to go to the shops on etc. when i put the bike away it was fine however when i got the bike out today i noticed the gear selector which you lift up or down with your foot to select the gears was in the wrong position. I put my foot underneath it to lift it up and to my surprise found that the selector was so loose that it was just hanging there . I got off the bike and I was able to select the gears by pushing the lever against the bike and then gently selecting gears . I am assuming that whatever holds the lever in place has broken or whatever holds the gear selector in position has dropped off. If it is a nut etc that goes on the end of a shaft I could try and find this I have found another gear selector on ebay so if I need one of them I could get one but there must either be a circlip or a nut that holds this gear selector shaft in place . So my question is what has come off ???? is there a nut or a pin / circlip etc that keeps the selector in place because at the moment it can be moved nearly all the way round like the hands on a clock and I would like to get it sorted so that I can give the bike to my son to go to work on. Any advice / help would be appreciated before I take the thing apart I wanted to check to see if it is something I can sort easily etc?