Big Red cam shaft placement

[JoeSuzuki]

I took the head and cylinder off my big red engine in order to replace the piston and rings. Now that I am about to put it back together, I noticed that there are no marks on the cam sprocket to align it for timming. So it the piston is at TDC, how do I set the Cam shaft for proper timing? Do I use the CDI key for reference?

[thefox]

I took the head and cylinder off my big red engine in order to replace the piston and rings. Now that I am about to put it back together, I noticed that there are no marks on the cam sprocket to align it for timming. So it the piston is at TDC, how do I set the Cam shaft for proper timing? Do I use the CDI key for reference?

The mark is only on one side of the sprocket, you must have it on backwards.

[JoeSuzuki]

So at TDC, this mark on the sproket aligns with what?

[Dirtcrasher]

The bolt holes for the cam sprocket themselves should be at 12 o clock.

In other words, at TDC on the compression stroke the cam lobes should be AWAY from the rocker arms by 180 degrees. Both rocker arms should have play in them at this point. This also helps set the ignition timing as it should be firing at this point or you have it 180 degrees off.

Ignition timing being off is nothing, just won't run. But cam timing can bend a valve if it is off. Best to double and triple check it and then run it over smooth with the plug out to be sure until you understand it.

[JoeSuzuki]

Alright, everything is back together with new piston and cylinder and when I pull the pullstart is sounds and feels smooth.
Now if I keep my finger on the sparkplug hole I can feel the compression but there seems to be a suction effect and the end of the pull. Could this mean the timing is off a bit??