An H-16 is a 1656.
Just to let you know there was no H15 there was just the 1556The H14 (1456) or H15 (1556) parts manuals will serve. Only the engines differ.
How it locks:
On the right side the hub is always keyed solidly to the axle. On the left side a tapered brass cone is always keyed solidly to the axle.
The large wingnut forces the tapered brass cone into a matching tapered funnel machined into the left hub. The friction locks the left hub to the axle. Then you can spin both wheels when you lose traction.![]()
Oh. Right. Sorry.Just to let you know there was no H15 there was just the 1556