What is the size of the top fork bolt on my 02 FLHTC? I went and grabbed a 1-5/8", but that isn't it, so I am assuming it's metric? The largest metric I have is 27mm and it's bigger than that. Also, do you use a wrench or a socket? I couldn't fit a socket in there?

 

You can buy the special tool, or do what I did, and go buy a cheap 35mm and cut it down.
Check out Georges garage for specialty tools

 

I use a 35mm box end.

 

on my o6 ultra it is a 36mm harley has a real thin one it comes with the tool kit
It is only about 1/8 thick it fit right in there. It is a box end any thing else is too
thick to fit in the tight space

 

It's actually 1 3/8" but yes the HD 36mm wrench from the tool kit works if you are careful.