hawk 250 stuck gear when warm
 

Hi guys, love the forum helped me so much, I have read all I can on the forums about this issue(at least I think). I adjusted cable, changed oil, and it still gets stuck in 3rd or 4th when riding for 5 to 10 min or so. usually fine if I don't go above 3rd but if I get up to 4th or 5th I cant downshift past 3rd (until bike cools down and even then I have to rock bike a lot to shift out)if that helps. I hope its not the pawl or fork I read about, if it is I cant seem to find any online.
Any help would be appreciated and ill try to answer any ?s you guys have