Ok heres one that has me stump. Got a 98 F3 with a blown lower engine case. Got a 96 motor which needed shims, lobes and a head bolt that needed to be drilled out and helicoiled. Got the 98 lobes and cams and swapped the pair on the 96. Replaced the timing chain because it was different between the years (have not replaced the lower timing gear). New manual tensioner installed. Head removed and head bolt drilled out with helicoil in place. New head bolt installed. Shims swapped between 98 and 96 so then, Intake is between 16-17 mm and Exhaust is between 21-22 mm. There was one lash that was as low as 8 mm on the IN side. After all this was done, bike kicks over perfectly but, still a huge top end rattle. Tensioner seems to be correct, any tighter and the bike idels low to stalling point (again, have not replaced lower timing gear with 98, still has 96 original in there). Could it be the valve that had a 8 mm lash? Maybe a bent valve or broken spring. How do I check this? Could I swap the 98 head in place, reshim and forget about rebuilding the 96 head?