Suzuki’s 2011 update of the GSX-R600 and 750 is very much like a MotoGP team’s midseason adjustment: minor in that it’s not a total redesign but moves steadily in a desirable direction. In the case of the 600, the 67.0 x 42.5mm inline-Four is rotated backward slightly, enough to allow it and the swingarm pivot to be moved forward. This shortens the wheelbase from its former 55.1 inches to 54.5. Shorter is better for quick handling, because when you turn the front, the wheelbase is the “lever” by which the steered motion of the front end steers the rear wheel.
In the outdated language of 40 years ago, the heavy-steering bikes admired back then “cornered as if on rails.” Locomotives actually _are_on rails; just try steering one. Today’s quick-responding bikes allow us to make midcourse corrections and quickly evade road hazards.A similar set of changes to the GSX-R750 takes its wheelbase from 55.3 inches down to 54.7. Claimed curb weight of the 600 decreases by 20 pounds—from 432 to 412. The 750’s 2011 diet trims it from 437 lb. to 419.
Resculpted 2011 GSX-R600/750 bodywork is said to be more aerodynamic and, like many other parts on the motorcycle, lighter than before. According to Suzuki, the new vertically stacked headlight alone shaved more than a pound. Tailsection mimics the current GSX-R1000’s.
Both the 600 and 750 receive the Showa Big Piston Fork (BPF) that was so much discussed during the final racing season of Suzuki’s many-time AMA Superbike Champion, Mat Mladin. As tire grip and speed of maneuver increase, chassis and component stiffness must do so as well. On this fork’s radial mounts are new Brembo calipers. As racing-minded readers know, Brembo has come to dominate Superbike and MotoGP starting grids with calipers designed for smooth, reliable operation and structural stiffness that translates to a firm lever. Brake discs are 310mm diameter.
Small details in the specification indicate the importance of racing to sportbike sales. Compression ratio for the 600 is up a tenth of a point, from 12.8:1 to 12.9:1. Compression ratio is fundamental to engine torque because peak combustion pressure is roughly 100 times the compression ratio. The greater the pressure acting on the pistons, the greater the torque at the crankshaft. But push the compression too high and you get destructive combustion knock. Engineers play a sophisticated game, subtly changing combustion chamber shape to give combustion the speed to “outrun” the chemical changes that lead to knock, even at higher compression ratios.
The ’11 600 spec also tells us this model’s forged pistons have been designed with the aid of FEI and fatigue analysis. FEI is Finite Element Analysis, a computer technique that can predict the stresses in parts. The aim here is to make pistons light enough to reach very high rpm but without creating within them any stress they can’t survive. This is why today’s very low “ashtray” pistons have such gracefully shaped undersides. That grace is the shape of design for low stress.
Pistons operated at state-of-the-art racing speed gradually accumulate internal damage—metal fatigue—that eventually produces cracks. The hotter the metal, the faster this occurs. The need to make MotoGP pistons last through three races has required manufacturers to combine stress and temperature studies into a computational tool that can predict cracking. Suzuki is naturally applying this valuable tool to production piston design.
Con-rods of sportbike engines have during the past several years been shot-peened to increase their fatigue resistance. Also aimed at durability under heavy load is the chromium nitride coating of the piston rings of these GSX-Rs, replacing the chromium used previously. Around Top Dead Center at the beginning of the power stroke, the piston rings must seal combustion pressure while the piston is barely moving. This is hard on rings because they need sliding speed to lift them off the cylinder wall on a wear-stopping film of oil. The cylinder wall near TDC is also very hot—another problem. An old-tech cast-iron piston ring would form micro-welds to the cylinder wall under these conditions, which would break as the piston started its down stroke, forming wear particles. This is prevented by coating the rings with very hard material of a melting point so high that it cannot alloy itself to the cylinder wall. This is not new for 2011, but it is interesting.
Count a fully adjustable 41mm Showa Big Piston Fork and Brembo Monobloc front brake calipers among the front-end changes made to the middleweight GSX-Rs. The rear suspension is similar in design to that of past models but weighs slightly less.
In the same category is the Suzuki Exhaust Tuning system, which is the familiar valve between the header pipes and collector. Under ECU control, it closes down partly at rpm or other conditions in which exhaust pipe waves returning to the cylinder are positive and would interfere with cylinder filling by back-pumping exhaust gas. But Suzuki’s 2011 brochure also relates SET action to throttle response. Throttle response and idle stability depend to a large extent on the exhaust fraction remaining in the cylinders. Exhaust dilution is what gives pure racing engines their irregular high idle and “sore throat” throttle response off the bottom. By reducing exhaust dilution, SET allows street use of tuning levels that would otherwise lead to such unacceptable throttle response.
A new item in the spec is the statement that cams in these GSX-Rs are the first production application of a technology developed in Suzuki’s racing activity. While the brochure doesn’t tell us what this is, a guess would be that conventional cam design assumes that all parts—cam, valve and tappet—are rigid. But at racing rpm and stress, nothing is rigid; all parts “ring” with vibration like bells. Valve heads vibrate like trampolines and camshafts bend and rebound. This vibration can interfere with controlled valve motion, causing valve float or bounce after closing. For valve-train stability at the highest revs, cam design cannot afford to ignore such vibrations.
As in the previous model, the engine is made shorter by vertically stacking its gearbox shafts, and engine braking’s negative influence on corner-entry rear-tire grip is reduced by a ramp-type slipper clutch. Inside the engine crankcase, pentagonal holes in the number 2, 3 and 4 main-bearing webs cut power loss from the back-and-forth pumping of crankcase air from cylinder to cylinder.
Do all these details make you tired? Relax and let the engineers make it happen. Controlling the details is how bikes have become as good as they are. And there’s more. Everything the engineers learn also reveals new questions. Answering them is the future.
WorldCom's collapse has already reverberated through jittery financial markets, and is likely to be felt in the wider economy, with banks, suppliers and other telephone companies devising strategies to contain their exposure.
WorldCom, built through rapid acquisitions, accumulated $41 billion in debts. Founded in 1983 as LDDS Communications, it became the nation's second-largest long-distance company and the largest handler of Internet data.
Company executives said they intended to remain in business, and have been promised new financing from banks to do so. ''We are going to aggressively go forward and restructure our operations,'' John W. Sidgmore, WorldCom's chief executive, said in an interview last night. ''I think ultimately we will emerge as a stronger company.''
While WorldCom has already cut its work force significantly, Mr. Sidgmore said last night that he did not expect further layoffs for the time being. He said he would remain WorldCom's chief but would be joined by a chief restructuring officer brought in by creditors.
Some creditors, however, have questioned whether Mr. Sidgmore, who has served on WorldCom's board for years, should remain in charge. Mr. Sidgmore took over as chief executive in late April after the board ousted Bernard J. Ebbers, one of the company's founders.
Shareholders, who owned what was once one of the world's most valuable companies, worth more than $100 billion at its peak, are expected to be virtually wiped out. With the bankruptcy filing, control passes instead to the banks and bondholders who financed WorldCom's growth.
Besides its own overambitious strategies and flawed accounting, WorldCom also fell victim to a glut of telecommunications capacity.
Cheap and plentiful financing allowed companies rapidly to build transcontinental and transoceanic fiber optic networks in the 1990's. The additional capacity resulted in lower prices for WorldCom's services, which include basic phone service and the transmission of Internet data for large companies.
Mr. Sidgmore said last night that he was opposed to breaking up WorldCom and selling its pieces, aside from an effort already under way to part with peripheral units like businesses in Latin America and some other operations. This approach would rule out selling UUNet, a large Internet backbone operation, or MCI.
But once the company reorganizes, and investors gain a better understanding of its twisted finances, WorldCom could become an attractive acquisition target, analysts say.
WorldCom's crisis deepened last month when it disclosed that Scott D. Sullivan, the chief financial officer, had devised a strategy that improperly accounted for $3.85 billion of expenses. Mr. Sullivan was fired by the board and David F. Myers, the financial controller, resigned.
The Securities and Exchange Commission has charged WorldCom with fraud and the Justice Department has begun a criminal investigation of its business practices.
In an attempt to regain its credibility, WorldCom's board elected two new members to replace Mr. Sullivan and Mr. Ebbers: Nicholas deB. Katzenbach, a private attorney who was attorney general in the Johnson administration; and Dennis R. Beresford, a former head of the Financial Accounting Standards Board and a professor of accounting at the Terry College of Business at the University of Georgia.
The two were also appointed to a special committee to oversee the internal investigation being led by William R. McLucas, the former chief of the enforcement division of the S.E.C.
WorldCom filed for bankruptcy shortly before 9 last night in Federal District Court in Manhattan.
Its international operations, which include companies in Brazil and Mexico, were not included.
The filing will relieve WorldCom of about $2 billion of interest payments in the coming year. Lower debt costs could allow WorldCom to compete on a stronger footing with its rivals, involving a potential price-cutting strategy that has analysts concerned about the wider strength of the telecommunications industry.
''WorldCom probably won't get any new big contracts from its current customers, but it probably won't lose any either, because of the difficulty and complexity involved in switching carriers,'' said Glen Macdonald, a vice president with Adventis, a consulting firm in Boston.
WorldCom, based in Clinton, Miss., scrambled in recent days to secure new financing from its banks after its cash dwindled to less than $300 million from more than $2 billion in May. WorldCom said last night that it had received commitments for up to $2 billion in additional bank financing. Such new loans to companies in bankruptcy receive top priority in repayment.
WorldCom must now deal with holders of $28 billion in bonds as well as 27 banks that loaned the company $2.65 billion last May.
But in contrast with other companies that have recently filed for bankruptcy, including Enron, WorldCom has many more tangible assets, generating actual revenues, lawyers said -- improving the odds that the company could emerge from bankruptcy as a going concern.
The creditors first in line to be repaid will be the three institutions -- Citigroup, J. P. Morgan and General Electric Capital -- that have pledged to arrange a loan of up to $2 billion, known as debtor in possession financing, to WorldCom. The lenders were comfortable pledging the funds in part because of the company's stream of customer payments, such as phone bills, one executive close to the company said last week. Citigroup is leading the new financing in part to protect what it is already owed by WorldCom.
WorldCom's bankruptcy filing, like Enron's last December, came on a Sunday. Companies often prefer to file over the weekend, because the status of any business transactions in process at the time of a filing would be open to question in court.
WorldCom's lenders and its bondholders were taking steps, even before the bankruptcy filing, to protect their claims. Just over a week ago, the banks that participated in the earlier $2.65 billion loan tried, unsuccessfully, to get a court order limiting WorldCom's access to the loan. The banks ultimately reached a settlement with WorldCom that placed few restrictions on the company's ability to use the cash.Continue reading the main story