Seemed Like A Good Idea At The Time
I associate overly long wheelbase with skating down the track on my butt, and with two-stroke piston sealing and socialism.
Like many another meddler with two-stroke engines, I was greatly taken with Bridgestone's GTR350. It had all-aluminum cylinders with chromium-plated bores, an advanced oiling system and -- best of all -- rotary-disk intake valving. I believed this engine had great potential for AMA road racing, and resolved to design and construct a competition Bridgestone.
The Bridgestone also had a six-speed transmission, a rarity at the time, but this feature didn't mean much because AMA racing's rules then specified a maximum of four speeds. I blocked off 1st and 6th, and had myself a pretty good close-ratio four speeder to work with.
My friend Bill Van Tichelt, of Vantech fame, collaborated on the design of the frame around which my racing Bridgestone was constructed, and it was fabricated in his shop.
One of my design requirements was to end up with a motorcycle long enough to accomodate expansion chambers leading straight out the backs of the cylinders, which is where piston sealing and socialism enter my tale.
I had earlier met a true genius in the field of two-stroke engine development, Walter Kaaden, who was chief engineer at MZ -- a motorcycle manufacturer in Zschopau, then sequestered behind the Iron Curtain in Germany's eastern half.
Kaaden fielded a "works" MZ team, competing in GP road races. His number-one rider was Ernst Degner, who doubled as an MZ engineer. Degner, by the way, bided his time until the DDR's government allowed his wife and children to vacation in Austria while he, too, was in the west with the MZ team. He promptly defected, and was quickly hired by Suzuki to assist with their competition efforts. Some say he left with MZ's drawings and test data. He certainly arrived at Suzuki with a head full of leading edge two-stroke experience.
At the time, it was by no means certain that the two-stroke engine would even achieve parity with four-strokers, much less reach their present absolute dominance in racing. Walter Kaaden was then doing more than anyone else to bring this about, and he was doing it with resources limited by the appalling performance of the DDR's state-managed economy.
I'm not sure Kaaden invented the rotary-disk intake valve, but he employed it with great effectiveness. He also seems to have been first to really understand exhaust expansion chambers, which had appeared earlier on DKW's racing bikes. But I am fairly sure he was first to appreciate that exhaust ports belong on the two-stroke engine's rear cylinder wall, which is the side rod- thrust presses the piston against and therefore is best sealed.
Walter Kaaden explained why his MZ's all had rear-facing exhaust ports, and that is why I hit upon the idea of reversing the Bridgestone engine's cylinders.
There were three difficulties to be dealt with before I would be able to implement the backward-cylinders idea: One was cooling in the area of the cylinder's exhaust port, which I believed could be managed with the simple cylinder shrouding that has worked in similar situations. The second was the laborious but simple matter of adding a little here and removing a little there to make the crankcase's cylinder spigots match the reversed cylinders. The third and last difficulty was accomodating the length of the exhaust pipes within the bike's length, as the AMA's rules forbade extending them back past the rear wheel.
I never got around to reversing the cylinders, but I created a long chassis to make the change possible and an experiment showed that the expansion chambers' outlet stingers could be moved up inside the rear cone without adverse effect on power or reliability.
After a number of air/fuel mixers were tried, I began to get really good power from the Bridgestone with a pair of huge (by the standards of the time) McCulloch "pressure pulse" carburetors. However, by this time I had become too well acquainted with the bike's tendency to lurch sideways when exiting a turn under hard acceleration. After it had thrown me down the track a couple of times, with consequences to my right knee that will put me under the knife yet again quite soon, I abandoned the Bridgestone and went on to other projects and other disasters.
I could have fixed my Bridgestone's habit of spinning out had I understood its cause. But enlightenment on that point did not come until some years later, when my mind was not overflowing with engine development details.