HARLEY-DAVIDSON XLX

CYCLE WORLD TEST

A human touch for a high-tech world

Here’s the Harley-Davidson XLX, the no-frills Sportster. It seats one. It doesn't have a radiator, a shaft drive, banks of solid-state instruments. There are no multi-anythings; not valves, nor pistons.

This test contains not one line about New! New! New! or Fastest! or Quickest! or Never Before!.

And we love it. The XLX hasn’t been parked since it arrived. The tourers, the racers, the dirt guys, L the technical freaks, are all arguing over whose turn it is to ride the Harley this weekend.

The XLX is an elemental motorcycle, stark in its simplicity. It has two wheels, two disc brakes, forks, dual shocks, two air-cooled cylinders, a single carb and air >

cleaner, two chrome exhaust pipes, a gas tank, an oil tank, a seat, a speedometer, basic lights, a battery, all out in the open and easy to spot and identify and understand.

The engine is Harley-Davidson’s unitconstruction Sportster motor, a longstroke (bore and stroke are 81 x 96.8mm), lOOOcc, ohv, 45° Vee. The cylinder head and cylinder are cast iron, just like the 1952 750cc sidevalve engine from which the current powerplant evolved. There are two valves per cylinder set in hemispherical combustion chambers, the valves open via rocker arms and pushrods operated by a set of four single-lobe cams arranged in the vertically-split crankcases, to the right and just below the cylinders. There’s a single 34mm Keihin carburetor (with an accelerator pump and an oiled-foam air cleaner) feeding both cylinders from the right side of the vee, through a Y-shaped manifold. The front cylinder’s exhaust exits forward, and the rear cylinder’s exhaust flows rearward; each cylinder has its own short, chromed exhaust pipe and muffler, with a balance tube linking the head pipes.

This is a dry-sump engine, with an oil tank bolted to the right side of the frame, under the seat. There’s a separate oil supply in the primary case for the duplex-roller chain linking the crankshaft and the multi-plate wet clutch, and for the four-speed transmission. Final drive is a 530 roller chain without O-ring seals.

Both one-piece connecting rods ride on the roller-bearing crankshaft’s single throw. The rods aren’t side-by-side. Instead, the big end of one rod is forked, and the narrow big end of the other fits between the fork. The three-ring cast aluminum pistons have high-peaked domes, but compression ratio is a mild 8.8:1, thanks to the tall combustion chambers. Steel struts are cast into each piston between the skirt and the wrist pin boss to help match piston and cylinder expansion rates.

Ignition is electronic with two advance curves built into a micro-chip control. A vacuum switch positioned on the carb bracket selects which curve is followed at any given moment: high vacuum, low load triggers the upper curve with more advance, sooner; low vacuum, high load has the ignition follow the lower curve with less advance, later. Advance is 8° at startup and advances according to rpm and load. Maximum advance is 40° BTDC.

Despite all those familiar features and specs, despite the heritage reaching back to the side-valve Model K motors, it would be a mistake to think this Sportster engine is the same as those before. It isn’t. The factory has continued with evolutionary improvements, improvements that become obvious when the 1984 XLX is compared with even the most recently previous Sportsters.

Take the clutch. It’s all-new (sorry, that just slipped out), with an aluminum alloy basket, aluminum-base friction plates, and a single diaphragm spring instead of six coil springs. The change to a diaphragm spring makes a dramatic difference, because it takes the amount of effort needed at the lever out of the bodybuilding catagory into the 20th century. And because the diaphragm spring has an over-center effect as the clutch is disengaged, the amount of force needed to pull the handlebar lever drops from an initial 18 lb. to just 6 lb. at the grip. More oil flows through the new clutch, helping to carry away heat, and the entire assembly is significantly narrower than the old clutch.

That narrowness allowed Harley engineers to add a 240-watt alternator on the clutch shaft, behind the clutch itself. The alternator replaces the 156 watt generator formerly mounted at the front of the crankcases and driven off the crankshaft by a set of three gears. A spin-on oil filter takes the place of the generator on the crankcases, with minor changes in the oiling system to accommodate this. The transmission output shaft has a new needle roller bearing instead of loose rollers and the output shaft oil seal is pressed into the crankcases instead of being held in place by a bolt-on cover. The result is that the 1984 engine is 13 lb. lighter than the 1983 engine, puts out more electrical power, has a lighter clutch pull and is mechanically quieter (thanks to the elimination of the three generator drive gears).

Rake and trail are 29.7°and 4.5 in., wheelbase 59.5 in. The XLX frame is made of round steel tubing; the backbone is formed by a single large tube running from the steering head, over the engine, and then curving down behind the engine to the swing arm pivot. Two smaller tubes run down from the steering head to form an engine cradle. Two other tubes branch back from the backbone to support the dual shocks and seat, and loop forward to meet the engine cradle tubes. The swing arm is rectangular steel tube and straddles the backbone; the swing arm pivot axle fits through the backbone tube and rides in two tapered roller bearings on the right (drive) side and in a single bushing on the left side. The rear axle is carried by sliding blocks fitting inside each end of the swing arm; chain tension is adjusted by turning a self-locking nut on a stud protruding from each block. The engine is rigidly mounted front and rear, and a steel strut bolts between the cylinder heads and the frame and doubles as a mount for the ignition switch, choke knob and horn.

The 3.0-qt. oil tank fastens to the right side of the frame, the battery box to the left. Both front and rear fenders are rolled steel. There’s a solo seat with a plastic base and vinyl cover and a 2.25gal. steel gas tank with a screw-in cap.

The left footpeg bolts to the primary cover; the right peg to the engine sprocket cover. The handlebars are conventional steel tubing. The forks have 35mm stanchion tubes and are non adjustable. The steering stem pivots in tapered roller bearings. There’s a single 11.5-in. stainless steel disc on each cast aluminum alloy wheel, a 2.15 x 19-in. front and a 3.00 x 16-in. rear. Tires are Dunlop K181 s.

The 5-inch headlight, rubber-mounted from a streamlined aluminum piece jutting forward from the upper triple clamp, looks small but packs more lighting power than its 35/50w low/high rating would seem to indicate—it is quartz halogen. There’s just one instrument, an accurate (60 mph indicated is an actual 59 mph) 85-mph speedometer with odometer and tripmeter, and warning lights for high-beam and low-oilpressure.

There are turn signals, two clamp-on lights attached to the handlebars and two stalked signals mounted on the rear fender support brackets. The signals are activated by pushing blade-shaped buttons on the handlebar control pods. Each set of signals—right and left—has its own button, and flash only as long as the button is held down. There’s no indicator light to show that the signals are working, but the rider can see the signal lenses. There’s one rearview mirror, on the left side, with flat glass.

Add up all the details and the XLX weighs 475 lb. on our certified scale, with half a tank of gas. That’s very light for a lOOOcc motorcycle. Sit on the XLX and it feels smaller than it is, partly because of that light weight and partly because the weight is carried relatively low, compared to a big-bore inline Four. The seat height is low, just 30.1 inches, adding to the small feel of the bike.

Reducing weight is one way to increase performance, but the Sportster is not a dragstrip missile. The XLX thundered down the quarter-mile with a best pass of 13.88 sec. and 93.75 mph, the: clutch slipped to keep the engine from bogging in the tall first gear and the engine powershifted at the maximum calculated speed in gears at redline (6200 rpm) since there isn’t a tach. It was on the second of five passes that we powershifted the Harley, yielding that 13.88 at 93.75. The clutch was never the same again. The XLX became reluctant to shift from first to second no matter what the technique, and our quarter-mile testing ended. In the flying half-mile, the Harley reached 108 mph.

It was different when it came time to test brakes. The combination of good brakes and tires and light weight allowed the Harley to record a spectacular 60-0 stopping distance of 112 feet. Control was excellent, although quick stops demand a hard pull at the lever; the clutch may be reformed but the brake still favors iron-pumping he-men at the controls. Stopping distance from 30 mph was also excellent, although not recordsetting, at 32 feet. The brakes also work in the wet, as a sudden rainstorm showed us. The fenders fend better than most, too, doing an excellent job of keeping water thrown up by the tires off the rider and bike. The Harley’s fenders were built for more than looks.

Trouble is, the dragstrip numbers don’t convey the feel, the character of this motorcycle. That can be a difficult concept to explain to riders used to the fastest, the quickest; riders prone to enjoy covering the distance from Point A to Point B in less time than a police helicopter.

Difficult until those riders are sent out on the Harley to cover more than a few miles, farther than the corner all-night market. The irregular beat of the 45° Vee breathing through short, dual mufflers gives the XLX a rumbling, growling—yet legal—exhaust note, leaving behind a subdued thunder. Accompanying that thunder is vibration, the real, honest throbs of large pistons shot down cylinder bores by the violent explosion of compressed gasoline vapors. The Harley has big pistons and turns slowly—60 mph in fourth gear takes just 3200 rpm—and that means the power pulses are big and distinct. The vibration is not the buzz and thrash of a vertical Twin; there’s a cadence to it that makes it seem normal and natural and very mechanical. It is the feeling of a machine at work, and if it lacks the silky smoothness of a refrigerator or a Buick, so be it.

The solo saddle is well padded. Some riders found it comfortable; others wished for a longer, wider seat with less of a rear hump. The pegs are a bit high and forward; the bars also high and forward. The suspension is middle-of-theroad, as compliant and quick to react as any other non-adjustable, simple forks and shocks, but not as good (and not as complex and not as heavy) as the multiadjustable, wide-range, state-of-the-art suspension seen on some bikes. First gear is taller than most, like second on a multi, and the gap between third and fourth is gigantic. The Harley handles both with torque, amazing quantities of an urge to move forward. Fourth is too low for fast cruising—four gears really aren’t enough—and the engine wants to pull another cog, a taller gear, a true overdrive perhaps. It’s smoothest at 55 mph, a motorcycle that runs best at the legal limit, and the vibration grows as the speed increases; at 65 mph cars in the single mirror are gross images and blurred colors, not distinct vehicles. The Sportster will run down the road at 85, 90, 100 mph; but the price paid for such speed is increasing vibration.

The price paid is not unreliability. The Harley-Davidson XLX is reliable. The problems encountered with the Harleys of years ago are gone, much as new quality control efforts have improved American cars. The XLX was given no special treatment, and it didn’t break.

It did use oil, two quarts in the first 1000 miles, perhaps because the rings need time to bed in. And it seeped a little oil, leaving a spot or two wherever the XLX was parked for long. The droplets came from the primary case, through the gasket and around the drain plug, and' blew back on the swing arm, rear wheel and rear disc.

The XLX didn’t use much gas, typically travelling 95 hard miles before requiring reserve, taking 1.8 or 1.9 gal. when the tank was filled five or 10 miles later. That’s about 58 mpg. On the Cycle World mileage test loop—a 100-mile circuit of city, open country and highway riding—at legal speeds, the XLX delivered 60 mpg.

This Harley-Davidson, this XLX, can be a surprising motorcycle. It is lots of fun in the city, booming through town and catching eyes with its metallic red (or black) paint and rakish profile. But it’s also stable and quick through the corners of a twisty road, speed past the apex limited only by dragging footpegs on both sides. The pegs drag too soon, but not so soon that a competent pilot on the XLX cannot startle a less-aggressive rider on a big Japanese sport bike. The Harley handles.

And it is fun. Fun to ride. The guys who ride Harleys understand that a motorcycle can be fun, can give a rider what he wants, without having the most possible horsepower. That’s the Harley. Its appeal is different from the appeal of the fastest, the quickest; its appeal is in how it looks and feels and what it is. The XLX is an escape of sorts, perhaps even a protest, a vehicle out of the complexities and pressures and cares of the modern world.

It is a motorcycle, plain and simple, honest and straightforward.