The bike Ducati should have built
After 23 years, Norman came out of hiding to make an already lightweight Ducati 800 30 pounds lighter with the adoption of his HOSSACK suspension. Since racing a Ducati Mach 1 in the 60s in Rhodesia, Norman a Ducati fan, always dreamed of making this bike.
Norman approaches bike design from an engineering first point of view. Styling is a secondary concern though this bike has gone a long way to making a bike that looks like it was meant to be. The tubing size and style were intended to match the original Ducati. Norman has always thought that the trellis type frame was there just for him. And this time round went back to basics with a tubular up right to match the rest of the frame.
The wide spaced and well triangulated trellis frame provided the ideal site for the wishbone base mounts. While this chassis is ideal for Norman's design there is one bike these days which Norman thinks would suit his design even better, the Panigale! Imagine what that would be like 20 lbs. lighter and with the engine further forward.
Norman is a very skilled CAD pilot and much work was involved in the basic layout, but that soon came to an end when the parts came together. CAD work can only take you so far, "there is nothing like touching the real parts" says Norman. CAD work can send you down the wrong path quite quickly and Norman now thinks the work would have been accomplished quicker and safer on a drawing board.
Everything from the middle of the frame forward has been rebuilt. In fact very little new metal was involved in the frame modifications. Most of what was cut from the original frame was used again. The frame modifications alone yielded an 8 lbs. weight saving. Norman did all of the welding himself on his favorite little Miller 165. There were only 9 major machine pieces and these were done by local machine shops.
The upright and wishbones are both made from one inch diameter 4130 tube and everything is TIG welded. The upright complete with axle came in at 7 lbs. although it could be lighter with thinner wall tubing but as this was a first off 7 would do. CAD analysis shows that a further 1.5 lbs. can be removed from the upright with ease. The axle and upright at that weight will quite significantly beat the Ducati in un sprung weight numbers too. In the construction Norman went right back to his first bike design back in early 1979 and its tubular construction. That design took its inspiration from the McLaren M23 top rocker and had nothing to do with girders with which it is compared.
The front damper is an Ikon (ex Koni) from Geoff in Australia. This is the same type damper as is on the HOSSACK BMW but this one has an aluminum housing. The valving may need some adjustment to narrow its range to suit the front end as against the rear where it is normally used.
The steering lock is improved to 30 degrees (the original was approx. 26) and the bars are raised by approximately 1.5 inches. These are just Norman's preferences to make the bike more human as he rides it to work every day. Instruments, lighting and switches are standard as is the wire loom, however Norman has a plan for that.
Norman selected the 800 Super Sport because it's the last air cooled version, and this made for a simpler and quicker build. Bypassing the radiator and fan and necessary plumbing made for a cleaner design process.
Also Norman was more interested in building a comparative bike, 'one to one' to the original Ducati 800 and so did not take the available advantage of moving the engine weight forward and thereby solving a known Ducati problem. As the HOSSACK wheel travels near vertically the engine could be about 3.5cm further forward in the frame.
The Hossack Experience
The main thing new riders find on their first HOSSACK ride is that braking has changed. The system has none of the mechanical dive that tellies are known for. There is still natural brake dive caused by weight transfer which is a function of the height of the center of gravity from the ground. Riders soon get used to this reduced dive and recalibrate their riding to the superior stopping power. The system also has a light touch giving a direct feel of what the tire is experiencing. This tire to road reaction is fed back to the rider through a freely riding, but extremely ridged upright which also has low un sprung weight.