Motorcycle Repair: Engine Assemble and Rocker Arm tension, honda cl 350, cam shaft

Question
Hello, I am sorry to bother you with an older bike question but the other guy's profile says maxed out, so... I have a 72 Honda CL 350 K4 and when I am assembling the engine I get all the way to the Cam Shaft, Rocker Arm assembly when disaster strikes.  Turning the engine by hand all moves smoothly until I place the rocker arms, the Points Housing and the Tach housing. When I turn the engine then, it is like it is getting caught on something and the right side of the engine (above the crankcase) wants to pull up and off.  Once I rotate past that point the engine settles back down and I can turn it a few time more but when i cycle back around it once again feels like it's getting caught and the whole thing wants to lift off again.  Help Please.... Do the rocker arms sit in a certain order?? Am I placing the arms with the lobes in the wrong spots?? I am just at a loss, this didn't happen the first time I rebuilt the engine.  Any useful words will be greatly appreciated.  Thanks.

Answer
I hope you are using a manual.  There will be marks on the camshaft, on the crankshaft, and these need to be aligned when assembling the top end.  If you do not have this timing correct, then the valves will open at the wrong times and hit the pistons.  That is what you are encountering.  Make sure the marks align with the camchain at the right tension and the problem should be solved...  Good luck,  Jan