WEll, i now have the bars (not fitted though as im stuck decorating the living room )

The OEM bars are tapped, and you screw in a reducer for the bark busters to bolt to.

Renthals are not tapped SO.....i guess im going to have to tap them. ive tapped small holes before but nothing that big.

I cant be the only one with 613's & barkbusters? what size tap do i need? (im not sure of the proper/enginnering methods for measuring things like this)