You are not limited to having Clip On Handle Bars the exact size of your forks. So ebay shopping might get a little easier for those of you who are limited to CyberShopping.
I acquired a set of used TELEFIX bars from Sac Cycles in Sacramento California. I had to throw in the Plug because they are a great bunch of Guys and Gals that helped me on more than one FrankenBike Project
I measured the ID of the clamp and it was a couple of MMs to large. Jason ran to the back and came out with a couple of thin split brass Sleeves. I thought he was nuts. But other assured me that it was OK.
It works as perfect as if they designed it that way. (maybe they did?)
I later hammered the 450 into a parked truck @ about 50mph and although the switches were upside down and the bar bent/cracked, the clamp didn't move.
Pix available on request, happier shopping to all