GS1100 vs CBX - page 4

The major reason for all this valve train irregularity is to be found in the rather shallow combustion chambers. Each intake valve is set in its own semi-hemispherical depression. During the intake cycle these depressions (each of which takes up about a quarter of the combustion chamber surface) channel the incoming mixture in such a way as to accelerate the pair of high-speed swirls normally found in the incoming mixture of 4VPC engines. The squish areas of the combustion chamber are designed to further accelerate these swirls during the compression stroke and thereby expose the maximum possible amount of fuel/air mixture to the spark plug to fan combustion. Suzuki claims that by thus speeding up combustion they can increase power, reduce the possibility of detonation and burn more of the air/fuel mixture. Because the combustion chamber is shallow and not domed, there don't seem to be any pockets where the mixture can be trapped and stagnate.

The piston crown is also extremely flat - flatter even than the fairly flat CBX piston crown-and Suzuki suggests several benefits of this feature. There's no dome to interfere with mixture flow and since the piston crown's surface area is reduced, there's less area to absorb heat and pass it to the rings and oil. To this end, the top ring is located low on the piston to keep it away from combustion heat. To get a respectable 9.5:1 compression ratio (compared to the CBX's 9.3:1) with the flat piston crown, the shallow valve angle and low-volume combustion chamber were necessary.

Suzuki is extremely proud of their patented "Twin Swirl Combustion Chamber" (TSCC) design and they're pushing it hard as the GS1100's main technical innovation. They claim that it requires less ignition advance and that with equal valve sizes the TSCC head will put out more horsepower per liter than Honda's "Pentroof" 4VPC design. The performance data seems to back them up.

Of course, the Suzuki can boast features besides just those in its engine. Like the CBX, 'the Suzuki's fork is an air-boost design, although the Suzuki's leading-axle Kayaba unit has 2.0mm bigger stanchions and 1.6 inches more travel than the Honda's center-axle Showa fork. In addition, the 1100's fork has a few extra gadgets, like four-position adjustable rebound damping. By turning a knob at the bottom of each fork slider, you can line up one of four holes of varying sizes with an oil passage to select more or less restriction. The GS also has a three-position spring preload collar on the top of each fork leg, which means that the air filler valve had to be located elsewhere. A hole in each stanchion just above the lower triple clamp is covered and sealed by another clamp. A hole in this clamp leads to an air passageway and is sealed from the passageway by a tapered bolt and an O-ring. The air passageways on the two stanchion tubes are connected by a small hose. The filler valve is on the left clamp. To fill, you back off the two sealing bolts to open the passageways. When you've set the desired pressure (up to 36 psi), you retighten the bolt to keep the fork legs from pumping oil into each other. If it seems complicated, it is. It usually took a little longer to set air pressure in the GS fork than to fill the two unconnected fork legs on the CBX (7 to 13 psi recommended).

The Suzuki has shocks with the same four rebound damping adjustments as the GS1000. The Honda only has three rebound damping settings, but it goes the Suzuki one better with its two- position compression damping adjustment.

This year the CBX's plastic swingarm bushings have been replaced with a double-row ball bearing on the right and a needle bearing on the left. The pivot bolt has been enlarged 2.0mm in diameter to 16mm and threads into the frame for strength. The swingarm itself has been strengthened slightly with thicker gusset plates. However, the CBX's swingarm looks pretty wimpy next to the huge extruded aluminum swingarm on the GS1100. It rides on needle bearings. Both bikes have tapered roller bearings in the steering heads. They also share V- rated tires and triple disc brakes. The Honda's tires are tubeless, and the Suzuki's discs have a series of slots designed to wipe the pucks clean.

The CBX has an oil cooler, which the GS lacks, and that cooler has been enlarged this year. However, the 1100 is the first Suzuki with special holes drilled and tapped in the crankcase to plug in an oil cooler. Previously, the difficulty of plugging an oil cooler into a Suzuki has driven some cooler makers to supply hookups for GS models which routed the oil around the top end and filter.

There's no gear indicator on the GS1100E, but it does have a special idiot light panel consisting of a drawing of a motorcycle profile with warning lights for brake light, taillight, headlight, rear brake fluid level and battery fluid level. The most useful of these is the battery fluid level light which uses a sensor built into the battery to warn when fluid is low, thereby saving the owner the trouble of removing the airbox to check the battery. Like the CBX, the GS also has separate lights for oil pressure, high beam, turn signals and neutral. The CBX has a voltmeter and the GS has a fuel gauge. Both machines have combined ignition/fork locks.

Honda has made arrangements with an insurance company to provide specially priced motorcycle insurance through their dealers to make it easier for people to afford a Honda. The CBX also carries two fringe benefits of this alliance. To reduce theft, the insurance company wanted the expensive CBX to have a lock. So there's a cable which wraps around a pole or post at one end and attaches to the helmet lock on the other. A short chain is provided to also secure your helmet. The cable is fairly convenient to use and it will discourage amateur or poorly equipped thieves. Of course, like almost anything, it can be sabotaged, but it makes the bike harder and more time-consuming to steal. Part of the cable's convenience comes from the locking compartment to hold it, which is located in the tail section. The door on the top of the seatback makes the compartment a convenient place to store maps, gloves, etc., because to open the compartment you don't need to remove any bungee cords you might have strapped over the seat.

Honda has reason to hope that any insurance break will lower the cost of owning a CBX. The Six's $4198 price puts it at a $529 disadvantage to the GS1100E, which goes for a suggested $3669. The slightly simpler Suzuki will probably also be cheaper to have serviced.

   

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