See following video for what can happen if you fail to propertly tighten/torque the crankshaft pulley retaining bolt. This is a Subaru, but Honda timing belts are same setup w/ keyed crackshaft timing belt sprocket.

I had this demonstrated to me when my son (away in college) hired a shop to replace crankshaft pulley due to slipping bushing. They failed to properly tighten crankshaft pulley retaining bolt, and bolt loosened. Woodruff key slipped out and crankshaft timing belt sprocket spun, followed by valves hitting the head. Required rebuild of cylinder head to repair.


good luck