Honda ATC 200 ES Choke sliding down.
 

Good day all,
For some odd reason my choke on my Honda 200 es keeps sliding down to being un-choked. I used to be able to pull up on the choke and it would stay there until I wanted to push it down. Now I pull up on the knob and it does not stay choked anymore. Were is the adjustment located to keep the choke active? I can't see anything to adjust other than possibly were it is screwed into the holding fixture near the headlight.

Any info on this would be greatly appreciated.
Thanks