I bought a used Manco Talon and it ran fine for awhile and now won't start. I replaced the battery and I am getting 12.5 volts at the pink wire on the ignition coil. I tried using starting fluid but still won't fire. I have no spark at the plug. Any help would be appreciated.  

try replacing the plug, the spark plug cable, and the coil, in that order.  

I put in a new spark plug, battery, and the ignition coil with spark plug cable. Still no luck.  

check the coil with an ohm meter

you should be getting around 14-15 ohms

you can also check all of the stator connections.

though the stators are really bad about going out on these.
as well as the cdi boxes.