How do you read dimensions of bolts I am trying to sell motorcycle fairing bolts I have a lot and I found somewhere that shows the sizes but how do you measure the metric bolts they say 6x14 6x16?

The first number is the diameter of the bolt in millimeters and the second is the length in millimeters.
So just like a 1/2 x 6 US bolt is 1/2 inch in diameter and 6 inches long...
a 6x14 metric bolt will be 6 millimeters in diameter and 14 millimeters long.

There is another measurement you may have to worry about with larger sizes. Namely the thread pitch. In metric you typically only see fine thread bolts starting at 8mm (8 millimeter diameter) and up.

You may see measurements like 8 x 1.0 x 40. This would be an 8mm diameter bolt 40mm long with a 1.0 thread pitch. The standard pitch for 8mm bolts is 1.25 so this would be a fine thread bolt.