Haulin' Hogs
HAULIN' HOGS
HOW TO HEAT UP A HARLEY
FIDING A CANDIDATE FOR a hot-rod project is easy: Just scare up a Japanese sportbike, install a batch of aftermarket speed equipment, and you’re on your way.
All of which ignores the fact that Harley-Davidson has clamped its V-Twin padlock on today’s large-displacement motorcycle market. And if new-Harley sales are thriving, so also is the sale of Harley speed equipment. Which caused us to wonder, what happens when a V-Twin motorcycle is introduced to hot-rod hardware?
Motorcycles that are built for speed are what happen, even if they are in a slightly different category than the road-burning
sportbikes that so often are the objects of the search for speed.
JON F. THOMPSON
We invited two well-known Harley-Davidson hotrodders to field bikes for this experiment: S&S Speed Equipment (Box 215, Viola. Wl 54664: 608/627-1497) and Carl's Speed Shop (9339 Santa Fe Springs Rd.. Santa Fe Springs. CA 90670: 2 I 3/941 -9385). The S&S entry was an unassuming 1990 FXR Low Rider, while Carl Morrow, proprietor of Carl's Speed Shop, sent along a more ostentatious 1986 Sportster 1200 owned by Pat Beyer, one of his customers.
The S&S Big Tw in possesses just one detail that tells an observer it is something other than a stock Harley, that indeed, it is propelled by the most powerful engine S&S offers in kit form. That detail is found in its cylinder barrels. Instead of being the familiar, rectangular Evolution items, these are round, chrome-moly barrels with cast-iron liners and bore diameters measuring 31 -Vi6 inches. With these barrels, and with a stroker crank that offers a 5-inch throw, this behemoth of an engine displaces I 14 cubic inches, or I868cc. and was dynoed. according to S&S's George Smith, at 163 horsepower at 6000 rpm.
Development of that sort of horsepower requires very efficient, high-volume flow of the fuel-air mixture. This starts with use of an S&S Super Ci 2 VIe>-inch Shorty carburetor. which feeds into a V-shaped intake manifold bolted to prototype S&S/Fast Company heads that use stock valve geometry and oversized valves-the intakes measure 2 inches, the exhausts an inch and three-quarters. Actuating those valves is a high-lift, long-duration S&S Super G cam. One final detail involves modification to the engine's hydraulic lifters so that they behave like solid lifters at high revolutions.
That's it. Except for a steering damper and Dunlop K591 tires, this Harley was a stocker. To duplicate the S&S mods, figure on spending $6000.
The Carl's Speed Shop Sportster was farther from stock. It wore regulation Harley heads, but these were flowed by Morrow. Additionally, the engine contains enough in the way of S&S flywheels, rods, cylinders and pistons to boost its displacement to I460cc. or 89 cubic inches. Valves are actuated by a Red Shift cam operating Andrews pushrods. and this engine, too. inhales through an S&S Super Ci Shorty carb. Exhaust gasses exit via headers and silencers built by Carl's Speed Shop.
Since this bike was built for quarter-mile sprints, it wears a Kosman extended swingarm. It also is equipped with Koni shocks and Performance Machine rotors and calipers. Mitchell wheels and a Corbin seat. Need to duplicate it? Bring your bike and about $6700.
Even considering the Sporty's chromed, extended swingarm. these Harleys offer little in the way of clues that each bike hauls ass. Those clues are reserved for sound and feel. The first comes when the rider thumbs the starter, and the stock H-D starter motors strain against the bumped-up compression ratios of those monster engines. When ignition occurs, the rider gets his next clue to these engines' performance potential. The combustion process in each creates a sharp, raucous bark of an exhaust note that is loud enough to set off burglar alarms on nearby cars as they settle into rough idles.
But there's a lot more to these bikes than lumpy idles and loud exhausts. Get them out on the road, twist their tails, and these built Twins streak off into the distance, though each one accomplishes the feat in a different way. Crank open the Big Twin's throttle, and it surges ahead.
right now. its engine producing enough midrange torque to raise the anchor of a good-sized warship. I fell, it probably could propel a good-sized warship. There is. in fact, so much power on hand that the bike's chassis is woefully outmatched, its anemic brakes and suspension nowhere near capable of handling the performance this engine develops. except when the bike is traveling in a straight line. More alarmingly, the bike's stock transmission also was unable to stand up to the strain. It scared us silly when it sheared some teeth off a gear and locked up solid during the course of a spirited street ride. The tranny was repaired using heavy-duty aftermarket pieces that would be a good idea if you plan on duplicating the S&S engine mods on your own Harley Big Twin.
The four-speed Sportster gearbox suffered no such failures. but, then, it wasn't asked to handle quite as much torque as the EXlCs transmission was. The Sporty's engine was cammier than the Big Twin's, and made its considerable horsepower in the upper part of the rev range.
Í hough these two engines make their power differently, both produce power sufficient to surprise any rider dumb enough to mistake either of them for an easy mark. To find out just how quick and how fast this pair was. we traveled to Carlsbad Raceway, pul resident hotshoe Don Canet aboard, and told him to drop the hammer. Drop it he did. turning 10.94 at 125.87 on the Sportster, and 10.99 at 123.96 on the Big I win. Top speeds were equally impressive. the Sportster cranking off a 145-mph pass at a closed desert test site, and the Big Twin topping out at 141 mph.
A little perspective is in order here. The last Sportster 1200 we tested went through the quarter-mile in 13 seconds flat at 100 mph. and turned a top speed of I I 5 mph. The Sturgis Dyna Glide Big Twin tested in our October. 1990. issue quarter-miled in 13.58 seconds at 98 mph. with an outright top speed of 106 mph.
Still, neither of these bikes, for all their considerable performance, is capable of running with multi-cylindered Japanese equipment. But it was never intended that they should be—not by Harley-Davidson. not by those who carried out the hot-rod work on them, and not by us at Cvc/c World At the outset, in fact. Morrow, a dyed-in-the-wool
Harley fan who's not above poking a little fun at the Milwaukee product, laughingly told us that hopping upa Harley was a bit like hopping up a shop air compressor.
Well, maybe. We can tell you this for sure: Both bikes work really well, as cruisers and as Q-ship drag racers. We just wish our shop compressor was half as much f un and worked half as well as these two hopped-up Harleys.0
