This hole luckily turns out to be the right size for the tap, so all you have to do is tap it. It is located right above the muffler on the cylinder. Just be careful that the tap does not go in too far and mar the cylinder inside. Any good hardware store should have a set screw you can use. You want a short one with no head/ just a hole for an Allen key. Use some Loctite or thick super glue on the threads.

AV8TOR