sloppy versus solid for racing
Hi all,
Yes, handling is the issue. I run my isos tight, and I have a nice Norvil head steady. I've contacted Kenny Augustine about blueprinting the frame too. It's a lot of trouble and expense to do that ($1k-$2k). The result I am sure would be an awesome handling bike for fast street riding.
However, in racing, there are fast transitions, lean angles, throttle use, and high speed dips that are never encountered even in the fastest street riding.
At each track I go to, I find 1 or 2 corners where the forces simply overwhelm the iso mounted frame. These are typically a fast transition from full lean one side to full lean the other side. Knee on the ground to knee on the ground. Usually between 80mph and 120mph. Examples: Turn 10 esses at Buttonwillow, turn 8A/B transition at Sears Point, turn 5 at Thunderhill. If there's a dip in the road (eg. Turn 3A at Sears Point or 6 at Laguna Seca) it's even worse. What I have to do in these turns is be suuuuuper smoooooth and baby the bike and not be WFO on the gas.
Top vintage racers all seem to be running Seeley or Featherbed frames if running Commando motors.
Buying a new frame and shipping to the USA would cost a little bit more than doing the whole isolastic blueprinting job ($2500). But that's not the entire expense as there would be new tank, oiltank, rearsets, etc that would be needed. :twisted:
Thus my though of either rigid mounting the swingarm or rigid mounting the entire engine, gearbox and swingarm. This would of course require changing the balance factor of the crank, but I'm in the middle of a new engine build, so I could do that easily.
If you look at the history of Commando racers from the Norton factory, by 1973 they were running a monocoque chassis (like a modern deltabox) with fuel and oil in the frame. The swingarm was rigidly mounted, and this supposedly was a huge step forward in rigidity and handling. The engine was still isolastically mounted because Denis Poore of Norton insisted upon it to have a link to the iso-mounted Commandos that they were selling for the street.
Dave
:twisted: