Update 011
So most of the frame centre section fabrication is now complete. Just have to strip it down, complete some triangulation, finish welds nicely and paint it. I’ve taken some images of the suspension and drive mechanisms while it’s easy to follow the design, before it all gets too complicated. The stand mechanism and exhaust routing will obscure most of this!
This first image shows the mounting of the spring damper unit. The left mounting is the fixed “body” end, braced into a load bearing plate that doubles as the rear engine mounting. The right “moving” end is mounted in a bearing on the rocker arm, which pivots about the lower bearing. This position is fixed to frame bars and braced by the curved plate (below shock) which also serves as a heat shield. The (far right) bearing, near tyre, is the intersection of the pull-link and the rocker arm. Vertical movement of swing arm is converted into horizontal compression force acting on the spring, which gives a smooth operation throughout the full range of travel. Ride height and damping rate is adjustable straight from the shock body.
This shot (from above) shows the jackshaft and primary and final drive chains. Although this design was unintended, I’m quite pleased with how its turned out. The primary chain has a separate tensioner (not visible) and gearing changes are very simple, but I most like the unused portion of the jackshaft which has other possible uses. I could attach another gear and use an electric motor to assist drive, or even reversing – but that’s a whole new project!
Here is the same view with the chainguard in place. It’s a strong (1.5mm) steel plate which covers the drive chains to prevent injury in case of failure, it braces the open frame top to add stiffness, and acts as a base for the seat to rest on. It will also keep heat and noise outside the driver compartment.
So there it is – quite compact! I have a 500mm seat height, to top of uncompressed seat ( not that its very spongy). That’s just below the “mystical” 20inch seat height mentioned in other FF circles and I can’t wait to see how it drives.
Next part is the exhaust – I’ve planned it all out! I will mount a lambda sensor within a “collector”, which will turn the single pipe into two, with an exit on each side, through a “box” type silencer which will act as an aero guide to help control the wake. This should keep me busy over Christmas, as I was intending to start the “swap-over” with the std C90 bits, but I’m going to keep it in one piece a little longer so that I can do the cooling tests. I did get a fresh MOT test on it, so I can ride this creation all though next year.