Enjoy the journey thru the Dark Matter Pro Street (Pictures do not do it justice!) Gallery!

DARK MATTER is a Complete Custom Pro-Street Motorcycle!  Built from the frame up. So it has a very unique and interesting story.

Dark Matter is owned by John Chism of Lincoln Nebraska. "I always look for creative and fun projects.  Having recently sold my show car.  I found Bill and his great pro street creation.  I truly am going to enjoy sharing this motorcycle and it unique and amazing story with other motorcycle enthusiasts." 

Originally the brain child and dream bike of Bill Birdsong.  The build started in 2012 with the Rolling thunder frame.  The build was completed in 2023.  Bill said: "This is my dream bike. I designed it and did all the assembly, including all the electrical. Various master fabricators fabricated the big sheet metal pieces based off my design. Every part of the build is detailed and documented in a set of comprehensive manuals and drawings with tons of photographs". 

A bigger, better American V-TWin from S&S

KEVIN CAMERON

S&S, OF VIOLA, Wisconsin, has leaped ahead in the bustling V-Twin business with an all-new 110to 139-cubic-inch air-cooled engine complete with emissions-legal fuel and exhaust systems. This new Vee, called "X-Wedge," was created to solve chronic problems of oversized V-Twins. It includes significant innovations in the areas of function, simplicity and ease of manufacturing.

Now a word about big: Anybody think a Chevy big-block 454 "rat motor" or maybe a Dodge Viper 506-inch V-b is big? Four V-Twins the size of the big gest 139-inch S&S X-Wedge would make a 55 7-cubicinch V-Eight. That calls for the most rugged compo nents available. Total engine weight, with intake and oil filter, is 150 pounds-S pounds less than an S&S 117-inch engine of traditional design.

S&S has long been known as a maker of big aftermarket carburetors for HarleyDavidsons (half a million sold). The company eventually produced such a range of aftermarket parts for Milwaukee Twins i that it became only a small stretch to begin making complete engines-of which S&S currently ships 8500 a year to customers like Big Dog and American Ironhorse. These have been ever-larger big-bore and stroker engines that have defined a new kind of high performance-one based on very large displacement V-Twins. Many a sportbike rider has been humbled by the rapid acceleration of Big Twins in the 100-inch-and-up category. Sportbike engines are optimized to fill moderate-sized cylinders with extreme rapidity. Elephant Vees fill much larger cylinders at a more leisurely pace. Air

and gasoline don't much care which it is. You pick.

What are the problems of traditional big-inch V-Twins?

1) Weakness of traditional pressed-together roller cranks. Flywheels vibrate, fret and even shift on the crankpin, especially at the first-to-second upshift.

2) Overheating. When displacement outgrows cooling-fin area, the engine can shed the heat only by running hotter. Oil gives up at some high temperature.

3) With a narrow Vee angle, as pistons are made bigger, their skirts eventually hit each other near BDC. When you machine the skirts for clearance, pistons rock in their bores, making noise and degrading piston-ring sealing.

4) Crankcase pressure variation in V-Twins is a 100-yearold problem, sometimes pushing oil up into the heads and keeping it there, sometimes wrapping oil around the spinfling crank, generating heat and drag.

5) Vibration was tolerable when rpm was low and pistons were small and light, but powerful big-inch engines can mix a lot of paint.

In case you didn’t know it, S&S employs a strong staff of capable engineers. The 160-inch special V-Twin that wins nationals in NHRA Pro Stock is their work-and it makes close to 350 hp. These are serious people.

They matched solutions to problems, as follows:

1) Nothing is stronger than a forged, one-piece crankshaft, like those used in Top Fuel drag racing. That’s what the new S&S engine has. Automotive-style, two-piece steel con-rods with pressure-lubricated plain bearings run side-by-side on the single 2.2-inch crankpin.

2) Each big alloy-242 head has been given 364 square inches of cooling-fin area, an increase of 30-50 percent over traditional Big Twin heads. Because pistons are round, so are the barrels, and their fin depth is greatest at the top-where the heat is.

3) To permit bores of 41/8-41/2 inches, with strokes of 4Vs43/8 inches, yet eliminate piston-skirt clashing near BDC, cylinder angle has been increased from 45.0 to 56.25 degrees.

4) X-Wedge has a new oil system in which oil is thrown by the crank into a collector from which it is pushed into the cam case through a one-way reed valve. Oil is scavenged

from the cam-case sump and sent to the oil tank. There are no oil return holes in the cylinders. Oil from the pump is sent to the two main bearings, from which oil is routed to the rod journals.

5)Low vibration requires light reciprocating parts-such as the short-skirt slipper pistons with stub wristpins used in the X-Wedge. This engine has been designed to vibrate less than a standard Evo-style engine in the rpm range of highway operation.

Why start over with an allnew giant Twin? All designs are ultimately outgrown by the power we learn to extract from them. Development pushes a basic design until all its flaws become critical. When they are, engineers must tackle them head-on and solve them.

If tradition is your major product, you must go carefully, for the smallest change in shape or feel or color may spell rejection. This is more art than engineering. But if, like S&S, you are selling industryleading high performance with a future extending into the emissions era, you put serious engineers on the problems and you crack them.

The new 43-pound crankshaft is a beautiful part, fully machined all over. To retain idle quality despite the very large displacement, crank mass is up 6 pounds from that of a 117-incher. The plain-bearing rods are Dana big-block Chevy related. The two main bearings are likewise of the sleeve type. When, in the 1960s, engineers discovered that the friction of plain-bearing and roller cranks was nearidentical, all subsequent bearing development went into plain-bearing design. X-Wedge benefits from that development, which in Top Fuel has shown its ability to carry loads of more than 15,000 pounds for each projected square inch of plain-bearing area. Plain bearings also support the cranks and rods of Formula One engines, now reaching 20,000 rpm.

Early motorcycle engines had rolling bearings out of necessity. They could tolerate “total-loss” oiling-a half-cup of oil in the crankcase, splashed on the parts by the crank and replenished every few miles with a stroke or two from a hand pump. As times changed, the U.S. motorcycle industry added mechanical oil pumps but kept rolling bearings because it was tooled for them. Today, all new high-performance

engines are designed with highly developed plain bearings.

The S&S Pro Stock engine has a 60degree cylinder angle. Where does XWedge get its 56.25 degrees?

Machined into earlier S&S cranks are electronic-timing trigger counterbores spaced 11.25 degrees apart (32 of these make a circle). To avoid having to rewrite this system for the new engine, the simplest solution was to increase the cylinder angle by this same angle. Result: 45 + 11.25 = 56.25.

Exhaust-port internal surface area is a critical part of aircooled cylinder-head design because almost half the heat picked up by the head comes through the walls of the exhaust port. This is because exhaust gas is not only very hot but moves fast with high turbulence—ideal conditions for fast heat

transfer. The port has therefore been made as short as possible, its internal area no greater than in earlier and smaller engines.

The pistons are short-skirted and carry their stub wristpins in a rugged box structure. Three conventional piston rings are used-two gas rings and a single oil-control ring.

It’s obvious that engines for the future must be emissions compliant-the rule that allows one kit-bike exception per

person per lifetime is no basis for viable business. It is for this reason that S&S has developed its closed-loop fuelinjection (CLEFI), which not only holds the engine’s emissions within 2008 legal limits, it is also able to adapt itself to changes in the engine or its specifications. Each cylinder has its own oxygen sensor, and the proprietary (that is, software written specifically for S&S) engine-control system treats each cylinder in NASCAR fashion-as a separate engine. The company is preparing to construct its own emissions certification lab for future use.

S&S’s engine-durability program impressed me, for I know how important this phase of product testing is. Engines must pass their variable rpm and load 200-hour test, and the company includes an 800-hour, 3200-rpm constant-load test as well. This is serious stuff, especially as compared with makers whose engines are just a bunch of parts that they hope will perform adequately straight off the computer screen.

S&S also has its own Spintron-a system widely used in NASCAR that spins an engine or parts of it by means of a powerful electric motor, allowing detailed analysis of parts motion in long or short term. This has become an essential tool for achieving valvetrain stability and durability. When I saw the S&S Spintron, it was busily running a valvetrain test of many hours. The new engine in its first form ran on the dyno at the end of 2004. It is now in its third generation in final development, with all major engine castings tooled, ready for production, which should commence in August, 2007.

Noise is always an issue with engines, and to keep as much mellow exhaust sound as the law allows, mechanical sound sources must be controlled. One of these has always been the valvetrain. Older Harley engines drive their cams with gears, but Morse chain has taken their place on more recent Big Twins. S&S went one better by having neither. Therefore the three cams in X-Wedge—two exhaust and one shared intake cam-are driven by a toothed Gates timing belt whose strength is in its carbon-fiber core. The toothed side is coated with a mesh that retains a solid lubricating layer (makes a person think of the wing pivot bearings in the F-l 11) while the reverse side is ground to make it pass over the three idlers smoothly. This belt is safely tucked away inside its dry timing chest on the right side of the engine, where it operates at oil temperature—180 degrees F, more or less. The cam lobes, inside the oil-pump cavity, drive needle-bearing roller tappets activating the four pushrods. This is a “free-spin” design, meaning that no matter how the cams are phased, the valves cannot hit the pistons. To change a timing belt, you put a wrench on the idler bolt to unload the tension, slip out the old and slip in the new.

A single 2%-inch (57mm) throttle body serves both cylinders, but there is a fuel injector in each head, spraying into its intake port. Positive overheat protection-very useful on air-cooled engines-is provided by three levels of skip-fire.

Now for the origin of the new engine’s name. When the program began in 2002, it was called “OTB,” for Out of The Box. Then it became “NG\(” for New Generation Vee.

Engineers used the codename “Fred” in casual conversation. Marketing people, we can assume, were not amused.

But why XWedge? Conventional Big Twins have hemi combustion chambers with valves angled fore and aft. The S&S engine has “wedge” combustion chambers with parallel valve stems.

Why the change? Hemi chambers originated long ago when maximum compression ratio was 5 or 6:1, which worked fine with flat-topped pistons. To get higher ratios and more torque as better, less knockprone gasoline became available, pistons had to grow tall domes. These increased piston surface area, absorbing more combustion heat, making them run hotter. To provide turbulence-generating squish-regions in which the piston comes very close to the head at TDC-required filling in the head on one or both sides of the valves.

S&S engineers decided instead to adopt the wedge chamber because it makes high compression possible with an almost flat-topped piston of minimum surface area. Its natural squish area is a useful tool against detonation. With X-Wedge’s large bore, plus valves and ports of modem shape, adequate airflow is no problem. Further, the wedge chamber simplifies rockerarm design. To reach the angled valves of a traditional chamber, each rocker had to be made as a long tube with a lever on each end in the shape of a Z. Because the tube is small, such rockers are springy. Having this extra “spring” in the valvetrain greatly complicates accurate valve control.

On X-Wedge, the rockers are of simple automotive type, made of stamped steel and mounted transversely to keep all valvetrain parts within the same plane. The result is a setup more than twice as stiff as in the traditional “Z-rocker” design. Another goal was to be able to make the rocker covers non-structural, and to eliminate the extra gaskets of the H-D-style “stacked” covers. The X-Wedge’s covers provide only oil-tightness, not support for moving parts.

You may have noticed the many automotive-style parts in this engine-plain bearings, two-piece rods, forged crank, stamped rockers and toothed timing belt. This is intentional, for it affords S&S a wide choice of automotive suppliers that employ the most modern manufacturing methods. The number of parts in the engine has been reduced by roughly onethird. Heads, tappet blocks, rockers and con-rods are all the same-no rights or lefts, fronts or rears. The goal of all this is what S&S’ers call “elegant simplicity.”

Five hold-down studs are used to retain each cylinder and head, a number that not only increases gasket clamp force by a useful 25 percent but also fits well with the layout of ports and valvetrain.

X-Wedge’s crankshaft drive end is compatible with traditional parts, i.e. Harley-style primaries. Engine mounts have been moved to a wider stance, so you cannot simply unbolt a current Big Twin and slide X-Wedge into its place. The rear engine mount, however, is on the same level as the gearbox mounting surface. The gearbox does not bolt to the engine crankcase. It seems a future engine might, given demand, be cast in-unit with its gearbox, but that would come later.

Vibration! To some, this is an essential part of the Big Twin riding experience, an emotional necessity. Look at those handlebars shake at idle! To others-especially longdistance riders-vibration is to be avoided. S&S engineers considered counter-rotating balancers but decided this would unacceptably change the simple shape of the engine.

As a V-Twin’s cylinder angle approaches zero, it vibrates more and more like a Single, whose circular shaking force cannot be reduced more than 50 percent by crank-mounted counterweights. As the Vee angle is increased, the engine becomes potentially more self-balancing, until at 90 degrees, a counterweight equal to 100 percent of one cylinder’s reciprocating weight will completely balance the primary shaking force (primary means at crank speed). More interesting to S&S is that the buzzier secondary shaking force (shaking at twice crank speed) becomes self-balancing at a Vee angle of 60 degrees. X-Wedge’s 56-degree Vee makes its vibration easier to manage than it is for 45-degree cylinders. Even though this engine is big, its vibration levels in the highway cruise range of 2000-3000 rpm measure somewhat lower than for a standard Evo-style power unit.

Because S&S currently supplies engines to several motorcycle manufacturers, provision has been made to alter engine appearance at will by measures such as changing rocker and sidecover style, or by various fin-edge treatments.

Very large engines produce so much torque that there have been clutch and gearbox problems, so S&S now makes its own clutch and gearbox. This direct six-speed is all-dogring-shifted-no sliding gears. This permits helical gears to be used, increasing the average number of teeth carrying the load, thereby raising the torque capacity.

S&S is helping mechanics to learn the new laptop-based “carburetion.” It’s hard for anyone who has mastered a traditional technology to start over as a lowly novice with something new. Electronic fuel-injection at first seems pretty different from classical brass jets and the interpretation of dark “mixture rings” up inside of sparkplugs. Trainees are provided with laptops as an instructor “translates” carburetion into EFI’s new language. Jet numbers become injector on-times, and the shaded mysteries of sparkplug reading become clear electronic signals from the oxygen, baro and temp sensors. It’s still the same combustion reality, just implemented in a new way. Each student constructs his/her own fuel curve based upon this information, then uploads it for testing on a bike on a dyno and refines it to achieve good running.

Because of the difficulty of conducting long-term road testing of the new engine in typical chopper chassis, S&S has constructed two test bikes of their own with up-to-date suspension and equipment. The engineers were quick to insist they have no intention of entering the motorcycle business, but these are attractive engineerdesigned machines, compact and neatly laid out, with an undecorated muscular quality. There is nothing extra. I found my mind running in all directions, seeing and seeking a kind of natural fusion of sportbike, bobber and custom. Something could happen here, but I’m not sure just what it is. These are big machines at 625 pounds, but there’s room in this world for bears as well as tigers and leopards.

In our era of large-scale offshoring of U.S. industry to China, I was delighted to see 80 CNC machining centers on the production floors at S&S and to learn that 375-400 regular folks are employed here at Viola, Wisconsin, and at the new distribution and training center in Lacrosse. Everywhere were pallets of machined cases, cranks and other parts.

These low industrial buildings, almost invisible up a ravine in an otherwise completely rural area, have clearly proliferated by a kind of architectural “cell division” as S&S has earned itself an expanding customer base.

Power? Oh, yes. So far, no flow work has been done on

X-Wedge's ports, but they flow as well now as anything in production. Refinements will come later. This engine will make an easy 135 crank horsepower in emissions-legal form. You take it from there.

And you will.