If there was any doubt Yamaha is devoting engineering resources to the idea of leaning multi wheel vehicles, this should erase those thoughts, it's the OR2T, a 4 wheel leaning motorcycle concept, based on the Tesseract leaning 4 wheeler from 2007. It looks like a well developed test bed for finding out how it works on the road and getting feedback for further refinement.
At first glance, the word "heavy" comes to mind, but without actual numbers it's hard to say and using advanced casting methods and light materials, it might be a lot lighter than it appears. If it works really well, the advantages may make this a practical motorcycle type vehicle, I say motorcycle type, because I'm thinking there are few places you could easily register a bike like this, what category would it fall into, and that's unfortunate, because it could be a real game changer.
Though there were many hurdles to clear, in doing so, the engineers were able to confirm the many unique characteristics of the LMW (leaning multi wheel) configuration at the same time: a good feeling of stability at very low speeds, a solid feel when riding in crosswinds and usability when going over uneven road surfaces.
It certainly does look like it would be stable at low speeds and the video below shows the suspension responding to uneven road surfaces. The one place where we can't see much detail is in the rear. I'm curious how that works.
For those of you who want to compare this to a standard motorcycle configuration, I think you're missing the point, vehicles like this may pull riders from those bikes, but it's really a new design only now becoming possible with current engineering and materials. Until you or I have the opportunity to ride one of these LMW concepts, let's keep an open mind. I know I'd like to try one out on the highway and put it through the obvious uneven gravel road scenario to get a feel for an extra two wheels in low traction situations. I'm looking forward to seeing where this design goes.