| Author | Message | ||
     Ulyssesguy |
Well curiosity got the best of me and i bought a 2004 XB12R muffler off of ebay so i could cut it apart and see what makes it tick... It cost me $23 to buy and $35 to ship go figure... so here are the pics...   It was not in very bad shape only needing some minor repair / paint, but i did'nt care i started tearing it apart right away.  The big problem i had was when the guy packed it he must have used a leaf blower to put the packing peanuts in the box because they were not only in the box but also inside every part of the muffler...  Including a Corona bottle cap how did that get in there?   This is the back end of the can cut off.  This is the front with the stuffing out so i can repair the dent.   This is the where the exhaust valve is.  And the peanuts were in there when i cut it open, this was the only way to get them out...  Let the mod begin i will left the picture speak for themselves.        I happen to have a Db meeter so i thought it would be a good idea the measure the sound level for the stock pipe the open header and the new pipe that i built... So here goes.  This is the Db measure 3ft from the rear of the bike and 3ft from the ground at idle sitting in my garage.  Here is a side by side of the stock can and the new one.  Ok here is the open header.  And here is the Db for the open header measured as before.  And finally the new can installed.  And the Db for my modified pipe.  I did this not because i'm cheap or because of any other reasons but to just satisfy my own curiosity and creativity it was a little bit of work and a lot of fun. After i finished installing it i decided to take it down the road for a test drive, not only does it sound great but it works better than the stock one according to my seat of the pants dyno... I Got lucky too during the test ride i was doing about 70 in a 50? and i got pulled over by and off duty cop... I was really lucky he let me off with a warning!   I also figured All of my fellow Badwebbers would love this info and find it very interesting! | ||
| Rubberdown |
WEll done! | ||
| Dudeman |
Thanks! and great work. Always wondered what the internals looked like. Do Mexican exhausts always have peanuts & beer?  | ||
| Electraglider_1997 |
This is the stuff I love to see and read. I'm assuming, right or wrong, that it has no fiberglass packing in it??? American ingenuity is alive and well. Thanks. | ||
| Treadmarks |
mmmmm peanuts and beeeer.... Nice job on a great walk through.  | ||
| Birdmanrh |
FYI, C-weighting is not how they test. They test using A-weighting and I think you will find it is a much higher number. | ||
| Ulyssesguy |
1)Electraglider_1997- I put new glass packing back in the stock location... i did'nt want to have it too loud. 2)Birdmanrh- Hmmm i thought the numbers were a bit low... I guess i forgot how to use that thing... At least it shows the difference between the stock pipe the open header and the new pipe since they were all measured the same way... | ||
| Chadhargis |
Yep...I the government uses A weighting. Here's a little snippet I found describing weighting: "For the most part, "A" weighting is used for relatively low level SPLs in the range of 20 to 55 dB and it's response curve correlates most closely to the ear's frequency response at these low listening levels. "B" is used for measuring moderate SPLs between 55 and 85 dB and the "C" weighting network is used for measuring SPLs of 85 dB or more. It is important to note, however, that any weighting network can be used at any SPL. For instance, the government uses the "A" network when measuring noise in industrial environments and at airports. In most cases, the type of network used will almost always be determined by the circumstances involved and/or a clearly defined set of rules and regulations." | ||
| Paochow |
Cool, Thanks for the Pics, neat to see how it works. | ||
| Baydog |
Uly Guy, I bought a muffler for the same purposes but haven't gotten around to cutting it open yet. This answers a lot of questions for me but I have to wonder about the packing. Is it only in the nose of the muffler? It wouldn't seem like it would do much there. I was expecting to see more perforations in the mid-section of the pipe and the packing there. Can you shed some light on this? | ||
| Teeps |
I gutted one and fitted an 18" Cheery Bomb glass pack muffler inside. Once closed up, looks like stock, only sounds better(?) I would not do this exercise again, and I only made two cuts in the stock muff. The $ spent for a Special OPS or Drummer is cheap for the results, considering the time involved in modifying the stock can. Unless you just got to have a project, that is... | ||
| Ulyssesguy |
Baydog- Yea the packing is only in the nose of the muffler, you can see that its right next to the interactive exhaust valve and part of the exhaust loop when the vale is either open or closed... My thinking was that this helps make it quieter. Teeps- Yea i wanted a project and it only took a bout 3 evenings worth of work... Besides i had to test out my new welder...  | ||
| Teeps |
Well, there you go... | ||
| Gotj |
Has anyone found the official sound level for a Uly per government testing? I expect its more than the 82 dB Ulyssesguy found although he was testing for comparative purposes, not legal compliance. | ||
| Teeps |
It depends on how they test for the noise. I know for cars (bike probably same) it's a drive-by test. This is why autos with manual transmissions, sometimes have weird ratios, particularly in 2nd gear. 82db takes into account for all vehicle noise during the test parameter. You can bet the Uly fan is not running during that test!  | ||
| Gotj |
Teeps, The 82 dB referenced in my post is the sound level found by Ulyssesguy (see above), not the official test. I'm interested in the "official" sound level, tested according to government protocol. My guess is that the sound has to do with road speed which is why so many bikes are geared tall. That way the engine won't be revving so high. | ||
| Gotj |
"I'm interested in the "official" sound level, tested according to government protocol. My guess is that the sound has to do with road speed which is why so many bikes are geared tall. That way the engine won't be revving so high." My guess was wrong. I have another 06 bike and just discovered a compliance sticker on it that specifies the dBA at a specific rpm, not speed. It didn't say whether the bike was in motion or stationary. Has anyone found that sticker on their Uly? I haven't. | ||
| Jammin_joules |
It is my understanding the gubmint does a 35mph drive by test, but what gear you use is unclear to me. |
