That BIZ motor mount ordered from the United kingdom website would cost you around $76 including shipping. That's not much more after you'd include shipping charges from BMI...
You
might be able to use an aftermarket 15-degree motor mount similar to the BMI picture you posted, but you'd need to find one that uses a single bolt for each of the lower frame clamps; instead of the dual-bolt design that BMI mount uses. Then you wouldn't need to remove that slotted metal bracket thats welded in between your 2 frame rails, that metal bracket would function instead of using the lower frame-clamps, just exactly like the BIZ motor mount does...
But first, you'd need to make absolutely sure the distance between your 2 frame rails (and the diameter of each rail) on your kart is compatible with an aftermarket motor mount.
I can help you figure that out; if you measure & post your karts frame rail diameter, and also measure the distance between your 2 frame rails where the motor mount goes. Measure your frame rail spacing from the 'center to center' points of those 2 rails, like the Info and pic you'll find at this link:
http://www.out2win.com/catalog/enginemount.html