Stuff a clean rag into the engine cases. Using a probe or small screwdriver, gently pry out the circlips. Push out the wrist pin and remove the bearing from the connecting rod. Throw away the circlips and bearing. Keep the piston, ring and wrist pin as get me home spares. Remove the intake manifold and the reed block.
Using a piece of Scotchbrite Red, lightly sand the cylinder bore. This will clean most, if not all, residual deposited aluminum. If you feel ambitious, clean the exhaust post with the Scotchbrite or 320 grade sand paper. Fill your kitchen sink (this really pisses the wife off...)with HOT water and 1/2 cup of TIDE. Clean your barrel vigorously and raise thoroughly with water. Blow dry your barrel with compressed air.
You are going to need the following parts to reassemble your motor:
head gasket-12251-GS2-621
wrist pin bearing-91102-GC4-601
wrist pin-13111-GC4-600
base gasket-12191-GBF-830
pre '96 piston-13110-GC4-610
pre '96 ring-
Inspect your reed block. If you see fraying on the edges, replace the reeds. On a kart engine, the fiberglass reeds have a very short life. Don't be a tightwad, get the carbon reeds and never worry about it again.
Reinstall the reed block and the manifold. Tighten the manifold bolts to 70 inch pounds. Lubricate your connecting rod small end with TRT NASA spec lubricant. If you don't have access to this, use 30 weight motor oil.