Harsay; I should have been more specific. I want to keep the bar end inserts from the stock bars. Those steel inserts are then reused to mount the Throttlemeister bar ends back on the new bars. In order to do this, an M16 X 1.5 tap is required.That's not a feasible drill/tap project. Most bar ends are 5/8 ID and that's already too large to tap, and even if it wasn't, try putting that size drill on a handlebar and drilling a precise hole. Now, for the 5/8 ID bars, you may be able to tap it with just enough bite to hold the bar ends, but I doubt it... Perhaps cut a cutting serration on the bar end threads to make it self tapping, the 5/8 hole is perhaps .2mm smaller than the threaded bar end. It's probably an M18 thread or similar.
You can use this same method but it's way too much work just to put a big weight out at the ends that look stock.