How To Determine What Wire Gauge You Have

Here's a handy chart to help you determine what wire gauge you are holding! A good micrometer will help you measure or you can buy a wire gauge online for a song. ( image for reference below)  
The Honda Shadows primarily use 18-24 GA wiring except for a few systems like  ignition switch, battery, starter, starter relay. Youll be able to see the difference if you are rewiring your bike. 
OH, and NEVER use all one color to rewire. ever!

Example of Wire Gauge Tool

AWG chart

AWG # Diameter
(inch)
Diameter
(mm)
Area
(kcmil)
Area
(mm2)
0000 (4/0) 0.4600 11.6840 211.6000 107.2193
000 (3/0) 0.4096 10.4049 167.8064 85.0288
00 (2/0) 0.3648 9.2658 133.0765 67.4309
0 (1/0) 0.3249 8.2515 105.5345 53.4751
1 0.2893 7.3481 83.6927 42.4077
2 0.2576 6.5437 66.3713 33.6308
3 0.2294 5.8273 52.6348 26.6705
4 0.2043 5.1894 41.7413 21.1506
5 0.1819 4.6213 33.1024 16.7732
6 0.1620 4.1154 26.2514 13.3018
7 0.1443 3.6649 20.8183 10.5488
8 0.1285 3.2636 16.5097 8.3656
9 0.1144 2.9064 13.0927 6.6342
10 0.1019 2.5882 10.3830 5.2612
11 0.0907 2.3048 8.2341 4.1723
12 0.0808 2.0525 6.5299 3.3088
13 0.0720 1.8278 5.1785 2.6240
14 0.0641 1.6277 4.1067 2.0809
15 0.0571 1.4495 3.2568 1.6502
16 0.0508 1.2908 2.5827 1.3087
17 0.0453 1.1495 2.0482 1.0378
18 0.0403 1.0237 1.6243 0.8230
19 0.0359 0.9116 1.2881 0.6527
20 0.0320 0.8118 1.0215 0.5176
21 0.0285 0.7229 0.8101 0.4105
22 0.0253 0.6438 0.6424 0.3255
23 0.0226 0.5733 0.5095 0.2582
24 0.0201 0.5106 0.4040 0.2047
25 0.0179 0.4547 0.3204 0.1624
26 0.0159 0.4049 0.2541 0.1288
27 0.0142 0.3606 0.2015 0.1021
28 0.0126 0.3211 0.1598 0.0810
29 0.0113 0.2859 0.1267 0.0642
30 0.0100 0.2546 0.1005 0.0509
31 0.0089 0.2268 0.0797 0.0404
32 0.0080 0.2019 0.0632 0.0320
33 0.0071 0.1798 0.0501 0.0254
34 0.0063 0.1601 0.0398 0.0201
35 0.0056 0.1426 0.0315 0.0160
36 0.0050 0.1270 0.0250 0.0127
37 0.0045 0.1131 0.0198 0.0100
38 0.0040 0.1007 0.0157 0.0080
39 0.0035 0.0897 0.0125 0.0063
40 0.0031 0.0799 0.0099 0.0050