Bought this bike off my neighbor for $50. It did not start, and he said it needed valve adjustment. So i got the valve specs and adjusted the intake to spec. But when i tried to adjust the exhuast valves, i had to turn the adjuster screw out to the point where the arm itself was touching the valve, before the screw got loose. And i still can't get my feeler gauge in. Any idea on what the problem is? Thanks for any help!!!