JT,Jersey Tom wrote:Establish your geometric and functional constraints... and really the rest just falls into place.
If only that were true!
The first thing you normally do is lay out your suspension's static pivot points, pushrod angles, rocker ratios, roll centers, cambers, casters, ackerman, toe angles, etc. Then you check for clearances under all conditions of steering lock, and suspension bump/droop. And that's when you find out that you have all kinds of interferences in your suspension parts.
As for new uprights on a 230kg(?) open wheel chassis with limited aero downforce, I'd recommend machined aluminum billet uprights and duplex angular contact bearings for the stub axles. Make sure that all of your suspension spherical joints are mounted in double shear, and that all of your suspension A-arms and links are loaded in tension/compression, and not bending.
Finally, since the powerplant/transmission is from a Yamaha motorbike, I'm assuming that the final drive is a chain and sprocket. So you'll want to be careful with your rear suspension's dive and squat geometry.
Good luck.
riff_raff