OP, I assume that your bike has been used and exposed to the elements and the paint has changed color because of this, even if you find a paint code chances are the paint will not be an exact match because of this.
In order to get close bring your bike in for the computer system to do the analysis...this may still yield mixed results unless the area that you have to scan is large enough for a flat scan etc.
The person mixing the paint may still have to use their eyes to adjust the color a little more.
Air pressure, as well as air temperature, will also influence the color.
If you are not doing a large area and only touching up chips, do the mix it yourself with fingernail polish on the other hand if you need to spray then you will have to go the route that I and others are suggesting.
Good Luck, Ben
__________________
"EVERY PERSON IS GUILTY OF ALL THE GOOD THEY DID NOT DO"
Voltaire
Voice recognition may sometimes create odd spelling and grammatical errors