2 ways - If you want the exact color you can go online and google the available color codes for that year. A good paint shop should be able to match it. If your only wanting to get it close you can take the parts (if they are the yellow you want) and they can visibly match and get pretty close. If you want a kinda comstom color that is the way to go since they can then lighten/darken it to what you want, add some flake, whatever. Hope this helps!
It's only illegal if you get caught.
If at first you don't succeed, use more lighter fluid
95% of Harley Davidsons ever made are still on the road... The other 5% made it home.
New Baltimore, Va '82 CB900c, 1980 CB985F/K 'Mutt"