My brother bought a used 88 fourtrax that was ticking very bad. I took it apart and found the cam and cam journal were spun. I replaced it with a refurbished Big Red head and cam (I used the valve cover that came with the new head as well), with new valves and so on. 10 hours later the darn thing spun again. Could it be the oil pump or oil line? What would you all recommend. I don’t mind putting a new head on this machine, but I don’t want to be chasing my tail and not fixing the root cause. Thanks in advance.