I haven't been on this site for over 10 years. I am finally in the process of putting things back together after a detonation event several years ago and saw this post from last year. in response, here is a link to something I posted in 2006 or so discussing my "MonoPlane Commando" 3 point linkage system ala Buell that I built for my MkIII Commando. It is referenced in old Access Norton posts but the links (including INOA site) are toast, it appears. Here is a link:
https://1drv.ms/f/s!Ajp0LHBjgmfvoSqvr_NSdPMyr8X4
The linkage setup is visually transparent and the design has (in my opinion) an OEM feel. It works very well and adds rigidity while maintaining the ISO functionality (minus the nylon washer side movement control which is rendered redundant). As designed, it pretty much requires a teardown to a bare frame and modifications (on the MkIII) to the air filter/battery carrier and oil tank lower mount. It can be constructed using a skill saw, angle cutoff/grinder, drill (preferably a drill press), LH/RH taps, & mig welder. Getting mounts laid out so the links are fully extended (midpoint, horizontal) in a static position is important. I stripped the frame first and blasted, phosphated and, recoated the frame afterward. The linkage components were blasted/treated and coated using KG Industries' GunKote. If I did it again I would have built a temporary oven and used Gunkote for the frame.
Is it worth it? I guess it is a "if you have to ask the price..." deals. It does significantly reduce/eliminate the inherent system "play" using washers with clearance gaps and the rod ends should maintain their precision without periodic adjustment. Handling is better (bike stays upright riding hands-off. It previously would fall off to one side fairly quickly without bar input) and handling is more precise. Vibrations are just as controlled as the stock setup. On the other hand, it is something of a commitment to implement the changes. The Most involved work involves the rear linkage. The head steady isn't that involved and you can substitute the Dave Taylor unit. The front linkage is a "plug-in"cartridge affair except for the frame mount bracket. I do think that the rear linkage is critical to making the whole system work however. And it is the link that takes the largest loads. The changes here included fabricating and installing an aluminum bulkhead and trucating the rear fender to attach to it (see photos).
I also reinforced the subframe. Probably worthwhile, but the size of the plate is a bit overkill IMHO. Plus you do not want to weld on the axle housing since it will have to be rebored to straighten.
Last comment regards adding linkage points. There had been some comments in the past. Any additional hardpoints above 3 only creates problems. A plane is defined by 3 points. Installing 4 points creates four possible planes so the system will be continually in conflict. Three points are good...
Dave Winship