I'm not sure and undobtedly someone with the factual knowledge will respond eventually but in the meantime:

I believe I have read that the cap covering the adjusting device needs to be pried off and underneath there is a small T- handle that is turned to adjust. There are some threads addressing this issue, as that is where I read it, but I don't know where or which ones they are.

You can also look around here as I believe that there is a detailed procedure somewheres on this site.

http://www.transbuilder.com/store-ie.html

Good Luck, my limited info might help until someone with actual experience responds!