Why dose me oil light come on my bike

Right about 1 quart (give or take about and fluid ounce or two).

Two ways to judge:

1: hold bike upright, remove derby cover (over clutch pack).
Pour primary fluid through derby cover hole until level comes up to just the bottom of the clutch plates.

------------------------OR-------------------

2: With bike on kick stand, pour fluid through derby cover opening until level is just below the derby cover opening.

Pull the derby cover off. Make sure bike is upright . Pour fluid in until its level is just above the bottom of the clutch pack in the primary cover

you CDI unit may have burned out or there's oil at the piston or there oil in the carborator

check you earth cable connections for corrosion, esp around solonoid, check for damaged wires at rectifier

The "filler hole" for the primary is the derby cover. Remove the derby cover, stand the bike straight up and pour the oil in until the level is at the bottom of the outer clutch shell. The "filler hole" for the transmission is on the right side chrome cover where the clutch cable goes in. There should be a large plug that takes a hex key or Allen wrench to remove the plug. The oil level should be between the lines with the bike standing straight up.

Good Luck
Steve