DIY: Installing baffles in muffler

[lawdog]

So I decided to build my own exhaust but wanted to do something a little different. I love the deep rumble of Rush Baffles so that is the sound I am going for. Low, deep, and mellow.

I decided to go with a set of 2 inch Rush Baffles and fiberglass packing around the baffles. I like fiberglass because it gives a smooth mellow tone. No tinny, or metallic noise. (Think chambered Flowmaster muffler verse sound verse Dynomax packed muffler.)

First I bought a used muffler for $25 on craigslist. I then cut it open, removed the rear chamber, and removed the 3 inner chamber pipes. Next I took the two baffles, grinded the welds off, and took each end cap off. Then I had my welder weld in the baffles and weld a plate over the center hole I then wrapped the baffles with the Rush factory packing then held it in place with wire.

I then packed one sheet of the MSR packing around both baffles to fill up the muffler.

Next I tacked it shut for the welder.

Here is a rough sketch of the plan.

Normal cruising the exhaust goes through the left baffle (driver side birds eye view) and dumps out. When the exhaust valve opens the extra exhaust flows out both baffles. I may play around with the valve and/or welding in a washer to make sure I don't loose any midrange torque.

Here is an inside pic of the baffles. You can see the louvers.

So then I had my welder button it up for me and I painted it with 2000' high temp gloss black. I thought about grinding the welds down to make them nice and pretty but really, who sees the top of the muffler. I also had him install two chrome turndowns which run $10 each at Autozone. Here are the finished pics.

Costs:
$25 used muffler
$64 baffles
$15 packing
$35 welder costs
$20 chrome tips
$159 Total Costs

A couple additional things worth mentioning. I bought three packs of exhaust packing and only ended up using one. I have two left over if anybody needs any. Also if you wanted to save money you could punch holes in the current pipes instead of welding in new baffles. Granted thats alot of holes to drill and I hope you have a drill press and a free afternoon.

I am working a bunch of OT this weekend but I hope to have the muffler back on the bike in a couple days. Once I get it back on and do some tuning I will report back.

Cheers!
Brett
09 XB12R

 

[ctmallam]

Sound clips!!!!

 

[lawdog]

So I got off work at 7 am, ran home, slept a couple hours then watched my son. While he was napping I threw the exhaust on just to give it a listen. Oh does it sound nice. A deep, mellow tone. Reminds me of my V&H big shot staggards I had on my Fatboy. I wasn't able to ride cause my son was napping but boy did it sound nice in the garage. I can't wait to take it for a ride.

Working a 12 today then watching my son so no time to finish installing this weekend. Hopefully Monday I can get it fully mounted and tuned. I am so stoked!

Ctmallam, not sure on the sound clip. I can record it on a small voice recorder but how would I upload it? Or I could shoot a video on my cell phone but its in some funky format.

This is great. Finally I am no longer riding the HD sewing machine. I am a lion, hear me roar!

 

[Nuage420b]

so basically skrew buying the baffles, just drill lots of little holes in the left pipe, and wrapped and fill it?

 

[lawdog]

Well I went with rush baffles because they are a proven design and I knew what sound I would get. But if you were frugal I don't see why drilling the current pipes would not work. Maybe not give the same exact sound but I couldn't imagine it sounding that much different.

If you went the budget route you could drill 1/4 or 3/16 holes along each pipe then wrap them with fiberglass packing. Then use wire to hold the packing on. Backfill with some more packing so it doesn't blow out and weld it back up closed. Try it and let me know how it works for you. I have some extra packing if you need it.

 

[12SX]

That really looks very very neat, let us know who it runs and sounds when you get a change for a ride

 

[303xb]

Great DIY. [up]

 

[Nuage420b]

yea PM me I will buy some packing off you. paypal work?

 

[DrogeN Omen]

nice. i have a second muffler to cut.

 

[lawdog]

So I got the muffler back on the bike Tuesday and I love it. Nice, deep, rumbly sound. Raw power. I would say its just a hare quieter then the Jardine. Definetely no lose of torque and roll on wheelies are no problem! I just bought a wideband so I am going to do sime tuning in May to get the perfect mixture. Right now I am very happy. It definetely turns heads! If you listen to the Sportster running on my earlier post thats exactly what it sounds like. If I get some time I am going to have SamIam do some runs for me while I record it.

Here are a couple pics.

 

[lawdog]

So I did a little tuning today and holy mother of all that it living! This thing is awesome. If you haven't tuned your bike you don't know what you are missing.

A little tuning has changed my bike into a snarling, shaking BEAST! This thing flat out runs. It is so much fun. Women and small children cower when I ride. Ok maybe not quite but everybody on the block will turn and watch me ride. LOL.

If oyu have not tuned your bike you are leaving so much potiental on the table. It just flat out runs now.

For my tuning I used OSB and richened it up to around 13.5 AFR. I just got a wideband so the next month I am going to tune it right. But for now it runs great, sounds great, and way way more torque then stock. Like rip the handlebars out my hands I have trouble keeping the front wheel on the ground all through first! So much fun!

 

[Nuage420b]

OMFG dude I owe you something!!!! sorry been studying for midterms and writting papers galore. I'm an idiot and completely forgot!

 

[samiam901]

Hey Brett you need to stop by and tune my bike then Hey guys I heard his pipe the other day and it sounds awesome. Pretty good job for the money. +1 for you Mr. Local Police Officer Guy.

 

[Nuage420b]

just sent [up]

 

[lawdog]

So after cruising around for a few days I honestly don't see a need to weld in a washer or any other restriction. With my K&N, cutout airbox, baffled muffler, and OSB programming there is way more torque across the powerband. My 2" baffles are larger then the stock pipes and there is no loss of torque. In fact next week I am going to wire the exhaust valve open and see what difference it makes.

Is the exhaust valve just for EPA noise control or does it actually help with low rpm torque. We will see.....

 

[Nuage420b]

Lawdog i spoke with a buddy of mine who has about 30 years of bike/car racing know-how. he said the washer wouldn't help anything but the sound. What he explained was that the back pressure is coming from the gasses escaping into the chamber and building up. Also that you really want the back pressure off and the free flow to happen as fast as possible for maximum performance. It was a much more detailed hour long conversation but that was the gist that I was able to comprehend. . . lol. he also suggested i just cut the exhaust off where the two headers meet and leave it at that!

 

[lawdog]

So a little update to my exhaust install.

After I installed the exhaust I just did a simple tune of running 10% richer then stock aiming for 13.5 AFR. I have a wideband so once I get it installed I will do some real tuning and dial it in.

Here are my thoughts on the project.I ran the bike with the exhaust valve open and closed for a week each. With the exhaust valve open I noticed a deep thump sound at idle and slightly louder and deeper at cruise.

I also noticed way more power in the 3-5k range with the valve wired open. I mean a very noticable difference. This could mean one of two things...

1. The exhaust valve is more for EPA regulations (sound and emissions) then to actually help increase torque.

or

2. I have a greater scavenging effect with the valve open at mid-range RPM so the bike is more efficient and producing more power.

Regardless of why I would say there is absolutely no need to weld a washer or any other restriction in the driver side pipe. In fact I am much happier with the valve wired open as there is a noticeable increase in power with 25-50% throttle and accelerating from 2k to 4-5k. It accelerates faster and has a deeper sound. I love it!

Right now I have the exhaust servo motor tuned out and I will probably yanking the wiring and cable at some point in the future.

I will try to get a video up soon. Right now with the ex and custody issues with my son I have been busy.

Brett

 

[lawdog]

So after reading up exhaust servo motors it seems the internet concensus is that the valve is used to control EPA noise levels rather then for tuning, back pressure, or torque. Anybody care to chime in on the issue. My butt dyno seems to confirm this as I noticed an increase in torque across the board with the valve wired open.

 

[jonzin]

Great write up.
How long are the baffles?

 

[Buell_Cru]

I do have one concern with how your tips are pointed. They should be pointed away from the rear tire so you don't get any oily blow by on your rear tire. Also the extra heat from the exhaust can change the tire charactaristics and actually make your rear tire washy if it gets too hot.