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The GR's engine layout, like the GS450's, uses a 180-degree crankshaft with a single gear-driven counter-balancer; upstairs, twin overhead camshafts operate directly on shim-and-bucket followers, opening two valves in each combustion chamber, but there the 650/450 kinship ends.

And the new-tech begins. A centrifugal clutch attached to the crankshaft's left end engages a 2.78 pound (44 ounce) auxiliary flywheel. This clutch, operating conversely of conventional go-kart types, disengages at higher

uneven 180/540-degree firing pulses of the 180 degree crank. You might not notice the long rollover in a smaller displacement 180-degree twin, but it would certainly be apparent in a 650. At low speeds, a light flywheel would tend to stop, stalling the engine - on the other hand, at high speeds a reductionof flywheel mass enhances acceleration and also aids engine braking.

This variable-mass system required another engineering first for Suzuki. The extra width of the clutch and flywheel mechanism at the crank's end would have required a lengthy starter-motor

parts - the check valves prevent oil from flowing through the jets. As engine speed and oil pressure increase, the check valves pop off their seats, allowing the jets to spray oil onto the underside of the pistons. Common in diesel engines, the system cools the underside of the pistons, a rather obvious stratagem when dealing with the heat created by diesel and/or turbo charging. In normally aspirated engines,  

the oil-jet spray allows higher compression or lighter pistons or both. This system first appeared on the XN85 Turbo, and Suzuki's 750 and 650 four-cylinder engines also carry it.

The transmission incorporates another oil-system jet, the purpose here to streamline manufacturing by eliminating the need to drill small, precise passages in the engine cases. Large

speeds. Its gripping "feet" face inward, clamping against the flywheel's inner boss rather than its outer flange as on normal centrifugal clutches. As the engine accelerates, centrifugal force throws the clutch feet outward, the clutch disengaging completely around 3000 rpm. Thus, the auxiliary flywheel freewheels at high speeds, independent of the crankshaft, and in effect reduces the crankshaft's rotating mass, while at low speeds, the clutch engages and carries the flywheel around with the crankshaft. The extra mass adds inertia, helping smooth the

shaft. To keep this shaft as short as possible, Suzuki fitted the pinion with a sprag-type clutch and moved the gear, clutch, and engagement drive to a separate shaft between the crank and starter motor.

In the crankcase, alongside the central web supporting the crankshaft's two inner bearings, two small oil jets aim up at the underside of the pistons. These jets, which look like a carburetor's, contain small check valves. At low speeds - when minimal oil pressure means all the oil pumped through the system must lubricate moving

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