I have only seen a s65 motor once maybe twice, and I thought that model had a flywheel with timing advance. If not please let me know for future reference and disregard below.
I need to know the problem, this is driving me crazy. This is really really really out way out in left field but hear me out. I think you said bike will start easy and idle fine, but as you increase rpm, bike stumbles, floods out and etc. What if at idle the timing is correct and as rpm increases a weak or broken advance spring is advancing timing to much??? Once unburnt fuel keeps loading up the plug motor get further and further behind.
Can you check the timing with the light as rpm increase to confirm it is still on the f mark?
Oh and also check the woodruff key for a partial shear or worn keyway on the flywheel that could cause misalignment. You can also confirm top dead center with head off. top dead center should be t on the flywheel to case notch.
I need to know the problem, this is driving me crazy. This is really really really out way out in left field but hear me out. I think you said bike will start easy and idle fine, but as you increase rpm, bike stumbles, floods out and etc. What if at idle the timing is correct and as rpm increases a weak or broken advance spring is advancing timing to much??? Once unburnt fuel keeps loading up the plug motor get further and further behind.
Can you check the timing with the light as rpm increase to confirm it is still on the f mark?
Oh and also check the woodruff key for a partial shear or worn keyway on the flywheel that could cause misalignment. You can also confirm top dead center with head off. top dead center should be t on the flywheel to case notch.