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FJ09 Muffler Disection


2and3cylinders
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I've read and seen videos for cutting open the Boom Box under the engine to remove baffles and welding it backup but has anybody verified what's inside the actual muffler portion?

Is it just a straight tube from the Boom Box?

I think it is if I recall now 

I was just trying to come up with a simpler way to open up the flow so to speak

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You might be thinking of this.  He shows the internals really well.

It's tempting!

2015 FJ-09 / touring bags / oil plug mod / Evotech rad guard / SW Motech bash plate / VStream touring windshield / Seat Concepts:  Sport Touring / Vcyclenut ABS rings (speedo correction) / Cosmo RAM mount

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Thanks.  I saw that video and a few others.

I'm looking for a cheap used 15~17 exhaust to play with.

I saw another that just used hole saws to open the compartments then sealed the holes for a better tone and less back pressure. 

Not very scientific and may do more harm performance wise without intake tweaks, a dyno and reflash.

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Gutting it is simple and sounds miles better, but not much difference to flow as exit port is the same. 
Headers and cat dump into the middle chamber, then a pipe takes it to the rear chamber, from there another pipe takes it to the front chamber where the exit pipe picks it up and out. 
Took all of 30 minutes to modify, then took it to a muffler shop and got it rewelded. 
I’m very happy with it. 
 

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2 hours ago, OZVFR said:


This is all the opening I needed for the modification. 

 

image.png

Is there a thread with pics or video of what you did?

I had seen the video posted above, and he enlarged the outlet but does the acousta-fil packing last "forever", because once welded closed it's not readily replaceable?  I guess a new "cover" could be gasketed and pop-riveted on.

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37 minutes ago, Ride365 said:

Winter blues already eh?

I can relate... by this time each year I'm already brain-storming projects and planning next years road trips.  I've already booked all of my vacation time at work for next year. 😁

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***2015 Candy Red FJ-09***

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28 minutes ago, betoney said:

I can relate... by this time each year I'm already brain-storming projects and planning next years road trips.

6:15 am, making an emergency trip to the grocery store for Thanksgiving green bean casserole supplies.    The rain is supposed to start by late morning, so I’ll take whatever riding I can get… 

19A35177-31B0-4AC2-97DA-F10B2C3BA8AC.thumb.jpeg.8d3c8969b3ce7c68c8fb9e784464d640.jpeg

Oh, and to stay on-topic with the thread, those mufflers on the Triumph sound absolutely angelic… 😀

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Just now, texscottyd said:

6:15 am, making an emergency trip to the grocery store for Thanksgiving green bean casserole supplies.    The rain is supposed to start by late morning, so I’ll take whatever riding I can get… 

19A35177-31B0-4AC2-97DA-F10B2C3BA8AC.thumb.jpeg.8d3c8969b3ce7c68c8fb9e784464d640.jpeg

Oh, and to stay on-topic with the thread, those mufflers on the Triumph sound absolutely angelic… 😀

Looks Awesome.  😎👍

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***2015 Candy Red FJ-09***

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I love the sound of a British twin in the morning it smells like victory

 But didn't they change the crank from a 360 or 180 to a 270

 Better for smoothness and big twin Bork but I remember my 73  triumph tiger 750

 Beautiful bike light handled pretty well had a disc brake on the front

 But when you were warming it up in the morning and you unscrewed the cap for the oil return tank to make sure it was flowing and blip the throttle to get it to heat up faster you could lose your horn when the bracket broke and flew across to the side of the garage

quite surprising

https://motofomo.com/triumph-speed-twin-1200-review/

https://www.classicbikeguide.com/1973-triumph-tiger-750/

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12 hours ago, 2and3cylinders said:

Is there a thread with pics or video of what you did?

I had seen the video posted above, and he enlarged the outlet but does the acousta-fil packing last "forever", because once welded closed it's not readily replaceable?  I guess a new "cover" could be gasketed and pop-riveted on.

There is no filling inside the stock muffler, and I never used any either.

I just cut out the S bend, and opened the rear partition directly behind the cat with a circular saw to roughly the same size as the cat exit.

Edited by OZVFR
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2 hours ago, OZVFR said:

There is no filling inside the stock muffler, and I never used any either.

I just cut out the S bend, and opened the rear partition directly behind the cat with a circular saw to roughly the same size as the cat exit.

 Is the cat connected to the S bend or to the header coming in the front and that's where you put the other hole?

 I know there's no packing in the stock boombox but the guy who did a major surgery added it

that's all I was saying

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3 hours ago, 2and3cylinders said:

 Is the cat connected to the S bend or to the header coming in the front and that's where you put the other hole?

 I know there's no packing in the stock boombox but the guy who did a major surgery added it

that's all I was saying

I’ve seen the video you referred to, and I thought it was really overcomplicating a simple job.
The cat is attached to the headers and empties into the middle chamber, a separate pipe connects the middle chamber to the rear chamber. 
A longer pipe connects the rear chamber to the front chamber. 
The exit pipe goes through the rear and middle chamber all the way to the front. 
the hole I cut is in the plate between the rear and middle chambers directly behind the cat. 
The S bend I cut out as close as possible to the plate and muffler exit point. 
it’s not that loud, specially at idle or up to 4000rpm, but has a nice sound that makes its presence known. After that it screams beautifully. 
I tour a lot so didn’t want an obnoxious drone.  
 image.thumb.jpeg.fb57a788658dd9bc950581febaf84c4a.jpeg

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