The design centers around an inch-metric thread adapter that you can pick up from McMaster-Carr. The female thread on the adapter is an M8-1.25, while the male side is a 5/8″-16 thread.

On the BMW, a $15 metric thread file saved over $600 dollars worth of head replacement or an alternative $300 machine shop bill. On other dirt and street bikes the savings was priceless. Outfitting ...