Go to the "Chain & No. Teeth" column and find the sprocket you are using now.  To find the next closest sprocket of a different chain type go up or down one row and read the sprocket type and number of teeth from the same column. 

The up or down choice is dependent upon the pitch diameters in the first column.  Choose the sprocket with a pitch diameter closer to the original pitch diameter.

Example:

You have #35 chain on your kart and want to convert to #219 chain.  The engine clutch has a 15 tooth sprocket now.  What  #219 sprocket do you need for your new chain?

1. Find the present sprocket (#35 - 15T) in the "Chain & No. Teeth" column.  Note its Pitch Diameter (1.8037).
2. One row up, the #219 - 18T sprocket has a Pitch Diameter of 1.7625.  One row down the #219 - 19T sprocket has a Pitch Diameter of 1.8595.
3. Compare all three pitch diameters. 
4. Choose the #219 - 18T sprocket because its Pitch Diameter (1.7625) is closer to the Pitch Diameter of the #35 - 15T sprocket (1.8037).