You can lookup your year and model on Partzilla, go to the relevant parts section, find the bolts you are interested in in the parts blowup image, find the number in the table on the right side and note the sizes of the bolts next to the part numbers.
You can also use Partzilla as a parts interchange source and to identify missing parts on a basket case.
We aren't always super prompt and sometimes we ask more questions than you'd guess that are relevant... But our goal is to help you repair and maintain your Honda ATV yourself, first and foremost! And help you have fun doing it!