I pondered for a while about putting a 24mm carby on once. In my speculation looking around my yard and garage I cam up with something that might be of help dunno? My delima at the time was that I would have to make a new intake.
This for me would have needed a slight angle to it and be bigger in diameter than my stock SCSW one.
I have a small collection of dirt cheep yard sale bikes stashed away. What I found when studying the diameter of the tubing with mic calipers at the fork crowns on them was that I had matches for it! I bailed on the idea and stuck with the 21mm upgrade I had for my high altitude tuning.
Yet a cool thing is right at a set of forks at the crown and a hack saw might give you the turn radius you are looking for? Then last simply weld that to a nice thick steel plate to represent your new intake bolt up point. Drill 4 screw holes and walla! Mebbe that will help?