Xl Tech
XL Tech
Harley at 100
Harley-Davidson just slid a new motorcycle under the Sportster, and that’s a good thing
STEVE ANDERSON
HARLEY'S PATTERN IS
emerging: Don't
expect every new
model to be as bold and radical as the V-Rod. One of the goals of the Twin Cam 88 program, for instance, was to create a better engine that couldn’t be distinguished from an Evo power-plant at 25 feet. That conservative revision set the stage for the V-Rod, perhaps the most radical departure in Harley-Davidson history. Now, with the 2004 Sportsters, Harley has returned to its conservative instinct, creating the first top-tobottom new XLs since 1957, yet you can hardly tell the difference as one rides by.
According to Product Planner Bill Davidson, that was intentional: “The positioning for the Sportster is very similar to that of the Twin Cam Beta Softail-we changed everything but didn’t change a thing. The customers already liked the looks, feel and agility. So we kept those, and improved the ergonomics and vibration.” According to Davidson, there were just a handful of overarching goals for the new Sportsters. First was improved ergonomics, particularly a lower seat height. The second was vibration reduction while maintaining the Sporty’s nimble feel. And third was to enhance and update styling. “We wanted,” says Davidson, “to retain the flare of the Sportster while creating the first brandnew bike for our second century.”
The biggest news of the project deals with the biggest complaint for years against Sportsters: Rubber engine mounts shield the rider from the inherent vibration of a 45-degree V-Twin. A small change, seemingly, but one which required a complete re-engineering of the vehicle. The 2004 Sportsters share only a handful of components with their predecessors, and are equipped with Buellinfluenced engines and a new chassis. The engine in many ways repackages Buell XB internal components into new cases with traditional Sportster looks.
“Every internal component of the engine aside from transmission shafts and gears has been analyzed and updated,” says Chris Bemauer, powertrain
manager for Sportster and Buell. “For performance, the ports, valves and valve springs, and chambers are the same as Buell XB-the 1200 Sportster and Buell heads are mechanically interchangeable.”
The Sportster’s engine mounting has both similarities and differences from Buell XB practice. As on the Buell, the engine and swingarm are now a unified package-but on the 2004 Sportsters, unique cases locate the swingarm pivot in its historic location, far back from the output sprocket. Two large, steel-and-rubber mounts with selective stiffness support the engine from beneath, rather than hang it from above as for the Buells. On both designs, non-adjustable tie-rods constrain engine movement to a vertical plane, permitting movement without allowing the rear wheel to move out of alignment with the front.
The rubber-mounting wasn’t a foregone conclusion. In 1998, the very inception of the program, says Bernhauer, “We thought about all kinds of solutions for vibration.
We had vibration-mapping data on single balancers, dual balancers, rubber-mounted frames and short-stroke engines. The group liked the rubber-mounted bike the best. To test vibration, we do a velocity measurement in inches per second at different rider interface points. The new XLs measure 1.5 inches per second at the handlebar, while the 2003 Sportster is 3.5. The 1.5 inches is very comparable to Beta (Softail) and Dyna at 80 mph at the handlebars. Yet it has a lot of character in terms of mechanical feedback. We didn’t want an electric motor; we didn’t want it sterile.”
The new engines retain obvious historic Sportster characteristics, from separate pushrod tubes to the four individual camshafts. The gears that drive these are the same, quiet, high-contact-ratio design introduced across the Sportster line in 2000-time-intensive select-fitting a thing of the past. Cam rotation is in the conventional direction, unlike that of the Buell XBs and Blast. Displacements are also historic, Harley product planning forgoing any opportunity to create a range consisting of, say, a 984 and 1350cc Sportster. According to Davidson, “We could get performance while maintaining displacement, and there’s a lot of equity in the 1200 and 883 names-most owners refer to their bikes as an ‘883’ or a ‘1200’ before they refer to it as a ‘Sportster’.” Both 883s and 1200s share the same 3.5-inch bore and respective stroke lengths of their immediate predecessors. And as on previous Sportster engines, the oil filter also mounts in its conventional location, filling the visual space of the long-departed generator. There’s still a timing cover on the side of the cam case, even though the new, fully mapped electronic ignition system now uses only a crankposition sensor for timing.
Harley sought significant improvements in durability, reliability and performance with the new engine. Bigger fins and an internal piston oil-jet cooling system help drop cylinder temperatures under equivalent conditions by 40 degrees compared to earlier Sportsters. Rocker covers are now two-piece instead of three, eliminating one possible leak point, and every gasket and joint in the engine has been improved. Performance of all 1200s has been enhanced to Sportster Sport levels and slightly beyond, the Buell ports and valves helping top end, while short-overlap Sport cams improve bottom and midrange power compared to 2003 1200s. Very substantial power increases (90 horsepower-plus at the rear wheel) will be available to anyone freeing up the still-restrictive exhaust and intake systems
and installing cams that let the engine rev further-something that wasn’t very
rewarding on previous Sportsters because of the high vibration that came with the higher rpm. Harley kept the Keihin CV carburetor on both 883 and 1200 engines, in part due to cost considerations, but also with the awareness that a lot of owners like to hot-rod their machines. “On fuel-injection versus carburetors, we’re watching the market and letting it drive us,” says Davidson One drawback that came with the rubber-mounting, though, was the loss of the engine as an effective frame stiffener. Constrained by styling to live within the visual package of the old Sportster frame, Harley engineers responded in the only way possible: They dramatically increased wall thickness and gusseting, resulting in a chassis they claim is 126 percent stiffer than the engine-frame combination of the 2003 Sportster-and one in which the total weight has increased by roughly 50 pounds. Helping ensure that added weight doesn’t eat up performance gains, gearing on both the 883 and 1200 was shortened, the higher revs being once again allowed by the vibration reductions on the new frame.
According to Davidson, ergonomic revisions were driven in part by an important target customer for the new Sportsters, the “65-percentile female.” As on the current Dyna models, the use of sheetmetal stampings rather than tubing in the seat-support structure allowed saddle height to be dropped an inch while maintaining full suspension travel-there will be no lowered Hugger models as a result. Handgrips have been thinned to a minimum li/8-inch from a Harley standard lV4-inch to fit smaller hands better while still allowing traditional 1-inch handlebars. Control efforts have been reduced across the board: Revised clutches lessen effort 25 and 8 percent, respectively, on the 883 and 1200 models, and new Nissin brakes front and rear require less effort for a given deceleration. The shift mechanism that improved gearchanges on Buell XBs now does the same for Sportsters. Sidecovers help keep oil-tank heat away from the rider, and also hide the new roto-molded plastic oil tank.
Cosmetically, both Roadster and Custom models benefit from the beefier 150-section rear tire replacing the 130 of earlier models, and both look better without a visible exhaust cross-over. The cross-over is still there, but it’s well hidden as part of the structure that supports the cantilevered mufflers that move with the engineswingarm mass, and aren’t directly connected to the frame. The Customs get much of their enhanced appearance from an all-new, 4.5-gallon fuel tank and pullback risers, while the Roadster tank shares the same outer panels as last year’s fuel tank; only the tunnel section has been changed to clear the new, beefier frame. The gas tanks are interchangeable, and H-D’s P&A division will be offering both.
So, what Harley has done with the new-for-’04 Sportsters is not go back to their Sixties roots and turn them into biginch fire-breathers, the role the Sporty once played. The company already markets two such machines-one the Buell XB12S Lightning, the other the slick and expensive VRod-and besides, if owners are intent on adding firepower, Screamin’ Eagle will be happy to sell the speed parts. No, instead, Milwaukee now offers slicker and kinder Sportsters that retain The Look that has attracted riders for decades, while, as Bill Davidson puts it, “What hurts is gone.” □
