Just buy a new cam chain tensioner , i pretty sure u cant buy a cam cap separate , it comes with the head , if it worn were the cam spins i say the head be worn to , it from not servicing the oil and filter enough , i seen high hrs on these 250 f were the guy has not change the oil enough and it were the journal were the cam spins and the cam itself are worn resulting in new head and cams , there is companies that claim they can fix them, and yes the cap is once piece on the 250 f 09 . use skf fork seals , they tend to last longer then the oem ones.