Installing and Testing the D&D Performance Exhaust
The OEM exhausts on the FJR are nice; especially if you appreciate the "stealth" they give to your "touring" bike as you ride all over the country. There's something unique about the way that the turbine-like whine of the intake overpowers the whisper-soft sound of the exhausts. But when has wisdom and discretion ever been my motto? It was time to breathe some masculinity into this Feejer!
There are tons of manufacturers of exhausts for the FJR1300. And there are a lot of basic reports from people who have swapped out their OEM cans for something different. Neither the manufacturer sites nor the reports from various owners have gone into much detail about the measurable differences between the OEM and aftermarket mufflers. I wanted to take the upgrade through a methodical series of measurements and report them here for others who might find the results worthwhile.
Based on the reports from various owners, all the various products made for the FJR are high quality and have different strengths and weaknesses. I chose the D&D Performance mufflers for a less-than scientific reason; their shop is about 10 miles from where I live. Their pricing was competitive and their products looked attractive. I chose the satin black on stainless option.
To ensure that I had comparable, repeatable results, I set up my testing and recording equipment in the empty parking lot of a nearby High School.
I measured off my distances and marked the locations of the bike, the meter, and the microphone so that I could replicate the setup with a reasonable amount of certainty.
I did several readings and recordings; using the highest sound level of each test and the "typical" audio sample from each pass.
My audio recorder was an Archos
20 Recorder with a personal computer microphone to capture audio straight
to digital in MP3 format (44.1 Mhz). There are some audio
artifacts introduced into the recording that I attribute to the hard
drive media of the Archos 20 and, possibly, the impedance of the mic.
Since the audio recordings are mainly for comparison purposes and the
audio artifacts affect all sound clips equally, I discounted their significance
to the results.
Unpacking and inventorying the kit from D&D I noted that no muffler gaskets were included. Knowing that salvaging the old ones is pretty iffy, I ran out and picked up two new ones at the local Yamaha dealership (pn: 3XW-14714-00-00, "Gasket, Muffler" about $11 each). Save yourself the trouble. The D&D connector pipes are designed so that they don't need them. Following the included instructions, I removed the OEM combo pipe/muffler from both sides, wrapped them up and stored them away for safe keeping. I then loose-fit all the D&D parts on the bike to check alignment and fit. WARNING: Make sure that the included clamps are oriented properly so that the bolt heads are easy to access for future maintenance. I had to flip the clamps on one side over so that both sides had the bolt heads facing down instead of toward the swing arm. It's much easier to orient them during the loose-fit stage than after you've already started tightening things up. The OEM mufflers use a captured flanged nut. You can either scavenge these from their "cage" by carefully flaring the inside retainer, or you can take one of the hanger bolts to a nearby hardware store and pick up 2 new ones (recommended). Continuing from the instructions completely seat all connecting joints and then tighten from the muffler hanger bracket forward; tightening the clamp at the joint between the muffler pipe and the cat/con last. Torque specs on the hanger bracket bolt and the clamps are 14ft lbs (20Nm). Once you've checked all your work, fire up the bike and listen for leaks. That's it! Set up to clean up took me all of 30 minutes.
Here's what you've all been waiting for. The audio clips and sound level readings from the before and after tests. The meter was set 5 feet behind the centerline of the rear axle, 5 feet to the right, and 8 inches off the ground. The mic was next to the meter; about 4.5 feet behind and 5 feet to the right of the rear axle. There were no sound level readings taken on the passing runs or the revs since those were mainly just for fun.
dBA = A-Weighted "500 - 10,000 Hz range, measures
the human ear's most sensitive range"
The Iron Butt Association Standardized Test
Okay. Ignore all of the above. None of it matters for the following. To participate in the Iron Butt Rally or other rallies that base their rules on the IBA rules, any bike with aftermarket exhausts must meet certain sound level restrictions. The details of the test are at their web site here. In summary, a measurement from 20 inches behind the exhaust, with the bike at "half redline", must not exceed 105 dBA As noted earlier, they have found that some Radio Shack sound level meters can be off by as much as 2 dBA Testing according to the IBA standard (20" behind at 4500 rpm) showed a reading of 95 dBA; well below the meter's margin of error. I am confident that the D&D Performance Exhausts meet the IBA standards for this particular bike. I advise others considering their own installation to take reasonable precautions and not depend on this report. Official IBA or Rally Master approval should be sought before showing up at a starting line. You risk being turned away without prior approval.
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