Originally posted by Buck Lovell on Sunday, 20 May 2012 in Buck Lovell's - American Biker Blog
NESS BIG SHOT AIR CLEANER & TRADITIONAL STYLE CYCLE SHACK SLIP-ON MUFFLERS INSTALLED
Like everybody says, the Harley-Davidson Big twin motor is essentially an air pump. The more fuel-air mix you can pack into those two cylinders at a single gulp, the more horsepower you'll get at the rear wheel…..The stock exhaust and air cleaner are the biggest impediments to free breathing with the Harley-Davidson V-Motor. California residents check your local regulations regarding exhaust and air cleaner. Sooner or later California bureaucrats will kill off the motorcycle industry in that state, and the associated tax revenues. Sorry…I got distracted. Replacing the restrictive EOM breathing apparatus of the Big Twin will not only increase horsepower but improve fuel economy, and reduce emissions at the same time. Regardless of what brand of aftermarket air cleaner, or what brand of exhaust product is used, the Harley-Davidson motor will run better, cleaner, and cooler with an intake and exhaust upgrade.
I opted to install Cycle Shack "SLIP-ON" mufflers, and a Ness Big Shot air cleaner on my brand new 2010 Harley-Davidson Dyna Glide. I located the bike a a Midwest dealership in mid 2011. Prior to installing these two products the motorcycle was tested by Randy Cramer on the house dynamometer at Dakota V-Twin in Spearfish, South Dakota. Dakota V-twin is the popular local and reliable motorcycle tune-up shop. This was done to determine genuine horsepower output, rather than rely on the factory brochure specification. The reading was a paltry 59 horsepower, this was with a thoroughly broken in motor (3000 plus miles on the clock). The dyno run also revealed that the motor was running on the rich side of stoic above 4000 RPM.
Cycle Shack mufflers and the Ness Big Shot air cleaner kit were installed as the motorcycle sat on the dyno (after a cool down period of course). Both are available from the Drag Specialties Fatbook. No tuner was installed at this time, I just wanted to get a dyno reading of the improvement resulting form a simple swap of the breathing equipment. Now the motor is running ever so slightly on the lean side below 3000 RPM, and damn near perfect above 4000 RPM. After the installation of the two product, horsepower went to 71. That's an 18- 19% increase in horsepower with just the swap of the air cleaner on the intake side and the mufflers on the exhaust side! And I got louder pipes to boot, which adds a huge safety factor. Even if they can't see me, they might hear me! One can only surmise that fuel economy will be improved as well.. At any rate it was well worth the time and small amount of cash to replace those two items in terms of horsepower, not to mention the motorcycle now sounds like a Harley-Davidson should…..loud pipes save lives, always!