Knowing the EPA laws would tighten later in the decade, Brett Smith proposed that S&S design, engineer and manufacture a proprietary engine that would keep air-cooled, pushrod vtwin fans happy for a long time to come. With the Board of Director’s support, Smith and Burgess sat down with a small group of S&S Product Development team members and explained their thoughts in October of 2002. Big Dog Motorcycle’s relationship with S&S on the X-Wedge engine really began around 4 years ago. BDM came to them with an idea/request to develop a new kind of engine that would be high performance, muscular looking, and perhaps even lower priced.

Turns out S&S was already working on this project. Their partnership and commitment to that engine helped solidify the project and keep it moving. Big Dog has been running around 10 engines for over 2 years, all versions of prototypes. The Rev 2, 3, all the way up to the 121ci in the Wolf. Without a doubt Big Dog Motorcycles has more hard miles on these motors than anyone except S&S themselves. Don’t underestimate this engine. It’s the future of American air-cooled V-Twins. Big Dog Built one of the first X-Wedge customs and are very excited about the Wolf with the 121ci engine which is exclusive to BDM.

The S&S X-Wedge — pronounced “cross” or “ex” — is a 56-degree, closedloop fuelinjected, three-cam, overhead valve v-twin designed to deliver the performance expected of an S&S engine, while complying with EPA laws. Initially, the X-Wedge will come in engine sizes of 117 and 121ci-with larger packages to come later. The 56-degree v-twin utilizes three beltdriven, large base circle cams; two exhaust cams and a common intake cam achieve almost straight pushrod angles that combine with automotive-style rockers and roller tappets to create an incredibly quiet, EPA noise conscious valve train. The X-Wedge is actually 5db quieter than a 41/8” S&S 117ci engine from 2000rpm through 5000rpm!

With almost perfect pushrod geometry; the X- Wedge can use automotive-style rockers. All you do is remove the rocker cover—which is just a cover and offers no valve train support—and there is easy access to the rockers. Also using a single-coil valve spring to help minimize valve train noise.

Induction on the X-Wedge is done with the new S&S single-bore throttle body pumping fuel and air into a wedge shaped combustion chamber contained in a head with a five stud bolt pattern and increased fin area for maximum cooling abilities. By design the X-Wedge got its name from its cross-wedge combustion chamber designed so that the intake and exhaust ports are in alignment with the valve stem plane to maximize performance. The head has the fuel injector mounted directly in it to improve injector aim for even more efficient combustion. A non-structural rocker cover that will allow various OE builders to design a look specific to their brand covers the aforementioned automotive rockers.

The heart of the X-Wedge—three cams driven off a dry belt. Visible in this cutaway is the Geroter oil pump. The Geroter oil pump picks up at the base of the case… increased efficiency and better flow. Additionally, a case-mounted reed valve eliminates and type of rotary breather valve.

With CARB and EPA compliance a top priority, S&S is determined to keep the American V-Twin alive and well far into the future. More information and photos can be found at: http://www.x-wedge.com/guts1.htm.

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