Also found this info on the Honda305.com forum from "Scottie"
EMO/LM likes Imron 6543UM, and this actually crosses to three different PPG codes, 71977, 71650, and 74359. The shop only had the chip for PPG 71650, and I compared it out in sunlight to the original part from my bike and it was a match, by all eyes in the area that saw it, including mine. The suggestion of Ditzler DPL71654K (from the Silver book?) crosses to PPG 71654, but it looked a little darker. It would probably look good on the bike, too, but I think the 71650 would be closer to stock.
Side note -- I also compared the 71650 to some test shots I'd made using the Valspar Restoration Series Ford (tractor) red, and it is also very close match to this. So, if you want to get by a bit cheaper, the Valspar Resto Series is a good quality alkyd enamel, and it's available at Fleet Farm or Tractor Supply stores at about $8 a quart. Hardener is available, too. Hahnda has used this with great results on his Dream. Some will make the point that alkyd enamels are an older type of formulation, and won't hold up like the new urethanes, but it's still a great option depending on your budget. Guys on the tractor forums argue about this a lot!
EMO's Imron 45040U crosses to PPG 33283, and while they didn't have a chip for this, the formulation is a very basic medium silver made up of black and silver flake, so should make a good match.
There's my little bit of research, such as it is. Next time, if I remember, I'll check on the black and blue.
Blue Imron 63203UH crosses to four different codes: 10419, 15958, 19126, and 19782. The main way to check these would be to check an original part against the paint chips, if they have them.
The black Imron 99U crosses to many numbers, some of which aren't even black! The main PPG number it crosses to is PPG 120, a generic black.