I've replaced the woodruff key the valves and springs and also the camshaft. Ran for all of 2 seconds. Tried again and back to square one. Shared woodruff key and broken camshaft. Lucked out on bent valves this time around. I've tried to upload pics but says memory to low to upload. Not sure what that means but ok.. my question is what's causing to the camshaft end to break and the woodruff key to shear off?

 

is their any marks on the piston wear it may have been hit?

 

No. Not at all. I did notice that on the top end the camshaft was hard to fully turn by hand even before I had replaced the valves. I was able to turn the camshaft until the lobe was touching the rocker arm and couldn't turn no more other then turning it the opposite way.. keep in mind when I did that I had the top end completely removed and the jug is also removed.