Real Pipes for the Low Rider S – Two-Into-One from Thunderheader
Even though there are a bazillion people out here in Southern California where I live, we can think of lots of good reasons to be one of them. Those positive reasons are called canyon roads! And these roads have created a red hot used-bike market for Harley’s 2017 Low Rider S.
Most of the bikes that Harley built on its Dyna platform handled very well. Then, with the introduction of the 2017 Low Rider S, aka FXDLS, Harley took the Dyna label to a whole new level of performance. For the ’17 FXDLS models, Harley added the Screamin’ Eagle 110 cubic-inch motor, which gives these bikes a lot more resources to build on. Unfortunately, these bikes were also the end of the line for H-D’s Dyna style swingarm big-twin frame.
But, like all stock motorcycles, the FXDLS has one huge performance drawback, the factory exhaust system. To start off, its sound quality lacks personality and then the 2-into-1-into-2 system doesn’t really allow that big motor to meet its true performance potential.
No matter what you ride, the crew at Thunderheader have an exhaust system for you. For this Dyna they developed a true 2-into-1 high-performance exhaust system that lets all of those 110 cubic inches breathe. But wait, you say breathe, we’re talking about an exhaust system, not an air filter or throttle body. I know, but an internal combustion motor’s breathing starts by filling an empty combustion chamber, and it requires a well performing exhaust system to clear the combustion chamber of all of the motor’s burnt gases.
The Thunderheader exhaust system features a muffler that produces a suction effect inside of the last foot or so of the exhaust pipe. This suction actually pulls the exhaust gasses out until they reach the reverse cone located at the muffler’s exit end. So we ordered their black system, part number 1035B, MSRP $845 and matching heat shields, part number 1131B, MSRP $253.
We followed along as the gang at Bartels Harley-Davidson did the install. Installing the Thunderheader was an easy job, it couldn’t have gone smoother; not only was every nut, bolt and bracket included, the instructions were also very complete. The install took just over two hours and only required hand tools. Not a hole was drilled nor a piece of the bike modified to fit the pipes. There are only two joints in the whole system, between the exhaust outlets in the cylinder heads and the end of the headpipes. Each head pipe is made from a single seamless tube section they welded together at the front of the muffler. Each of the three form-fitting heat shields is an exact fit. The hardware kit included two brackets to support the system. One of the system’s big features is the bracket that mounts to the transmission; its forward mounting hole is slotted, that way you don’t need to completely remove the bolt from the clutch cover. They also included new clamps for the heat shields. The only parts that were reused were the two snap-rings and flanges for the cylinder head exhaust port-to-head pipe joint.
The completed installation worked fine; the sound quality was fantastic, much deeper and mellower than the factory pipes. But the real deal was the overall performance improvement of the bike, it was like a brand new day in a more powerful world. The Thunderheader is a good complement to what we think is one of Harley’s best looking and riding bikes.
If you ride a Harley, Thunderheader makes a set of pipes that’s right for you!
4141 Lincoln Blvd
Marina del Rey, CA
By: John Sullivan
THE THUNDERHEADER SYSTEM NOT ONLY GAVE THIS LOW RIDER S A GREAT LOOK AND SOUND, IT REALLY WOKE UP THOSE 110-INCHES OF SCREAMIN’ EAGLE V-TWIN.
OUR STARTING POINT, THE BIKE HAS BEEN RAISED UP ON A LIFT, AND ITS SEAT AND THE FACTORY EXHAUST SYSTEM HAVE BEEN REMOVED. IF YOU ARE GOING TO WORK ON YOUR OWN BIKE, WE DO RECOMMEND THAT YOU BUY THE APPROPRIATE SERVICE MANUAL; IT MAKES JOBS LIKE THIS SO MUCH EASIER.
THE OXYGEN SENSORS ARE THREADED INTO THEIR BUNGS AND EXHAUST FLANGE MOUNTS AND SNAP RINGS ARE INSTALLED ON THE TWO HEAD PIPES.
THE MUFFLER IS BOLTED TO THE MUFFLER SUPPORT BRACKET; ITS NUTS ARE ALSO THREADED ON FINDER TIGHT.
THE THUNDERHEADER EXHAUST SYSTEM COMES FULLY ASSEMBLED; IT IS PRECISION WELDED TOGETHER.
THE EXHAUST ASSEMBLY IS ATTACHED TO THE DYNA’S TRANSMISSION CLUTCH MECHANISM COVER.
THE THUNDERHEADER’S MUFFLER SUPPORT BRACKET HAS BEEN BOLTED TO THE TRANSMISSION END COVER.
THE THUNDERHEADER’S EXHAUST PIPE MOUNTING CLAMP GETS FITTED OVER THE REAR CYLINDER’S HEAD PIPE AND SLID DOWN TO WHERE IT IS WELDED TO THE FRONT CYLINDER HEAD PIPE.
THE ENDS OF THE EXHAUST ASSEMBLY’S HEAD PIPES ARE CAREFULLY SET INTO PLACE IN THE EXHAUST PORTS ON THE CYLINDER HEADS…
AND THE EXHAUST FLANGES ARE FITTED OVER THE CYLINDER PORT STUDS AND THEIR RETAINING NUTS ARE THREADED ON FINGER TIGHT.
THE CLAMP THAT WAS FITTED OVER THE REAR CYLINDER HEAD PIPE IS BOLTED TO THE EXHAUST PIPE MOUNTING FLANGE THAT IS ON THE LOWER FRONT OF THE THUNDERHEADER EXHAUST SYSTEM’S MOUNTING BRACKET.
NOW ALL OF THE SYSTEM’S MOUNTING BOLTS ARE TIGHTENED UP: STARTING WITH THE HEAD PIPE TO CYLINDER HEAD MOUNTING FLANGES, THEN THE MUFFLER MOUNT AND, FINALLY, THE CLAMP ON THE REAR HEAD PIPE TO MOUNTING BRACKET. LASTLY, THE THREE HEAT SHIELDS ARE ATTACHED AND THE WHOLE SYSTEM IS CLEANED BEFORE THE MOTOR IS STARTED.