M50 fiberglass rebaffle for low $$$ (merged) - Motorcycle-Journal Forums

diamond_jim · 04-15-2008, 07:39 PM

Compared to stock, I love the sound of M50 pipes that have been debaffled and demickey'd. However, I've always thought they were a little loud when I accelerated hard and that there was a little bit of a high pitched sound mixed in with the deep growl. Some of that high pitched noise is valve noise and some is resonating from the mufflers themselves. I've wanted all that deep growl but get rid of those higher pitched noises. So after experimenting a lot, I found a low $$$ fix that tames the volume just right and makes for a better, deeper sound.

So, here's the tutorial:

1. Get a pack of fiberglass muffler packing used to repack sportbike mufflers. I got this pack for $6.50 at a local bike shop. The piece I got was about 14" x 12" and about 1" thick uncompressed in the bag.

2. Get a piece of masonry wire mesh (used for things like interior rock work around a fireplace, etc). A sheet is about 2'W x 8'L and has a tar paper backing. The wire mesh is pretty stiff and has a great springy action when rolled. I had some laying around. A sheet costs about $5 at Home Depot/Lowe's.

3. Cut two pieces of the wire mesh about 8" long and about 6" wide. I've experimented with several different sizes and lengths so I'm giving you the dimensions of what worked best.

4. Cut two pieces of fiberglass muffler packing about 8" long and about 6" wide.

5. Now find a spray paint can. (use blue paint because we all know that blue is always faster!) Now roll a piece of the wire mesh around the paint can. Be careful to roll it nicely and not force it and cause it to bend. We want to use the spring action that is inherent in a piece of nicely rolled wire mesh.

See the accompanying post for the rest of the steps...(just above or below this post, depending on how your posting time/dates are set)

diamond_jim · 04-15-2008, 07:58 PM

This is part 2 of how to rebaffle M50 stock pipes with fiberglass. See the accompanying post #1 (just above or below this post, depending on how your posting time/dates are set) for the first 5 steps.

Continued...

6. Find a piece of 2" PVC pipe that's about 8-10" long. It works better if you have some kind of flange or fitting on one end. I'll explain later.

Wow... I just happen to have a piece laying around...

7. Now you are going to roll the wire mesh a little tighter. Roll it nicely around the PVC pipe just like you did on the paint can.

8. Let it overlap about 1/2" and trim off the extra.

9. Now wrap your wire mesh around the PVC again and then wrap the fiberglass muffler packing around the wire mesh and trim it so that it looks like this:

The PVC pipe will not remain in the muffler. It is used only to mold the wire mesh shape and as a tool to help place the fiberglass and mesh in the exhaust.

10. While holding the fiberglass/wire mesh tightly around the PVC, slide it into the debaffled pipes.

11. Slide it in several inches. This is were the flange or fitting on the PVC pipe helps to slide the fiberglass,wire mesh in the exhaust pipe.

Once in, pull the PVC pipe out. The spring tension in the wire mesh presses outward against the fiberglass and holds it tightly in place. In the above pic, the fiberglass is slid about an inch so that the camera could capture it. Slide it in further than this though.

Now do the other pipe the same way.

Be sure to use the paint can then PVC to roll the wire mesh. If you go straight to the PVC it's more likely to bend the wire as you try to roll it. Don't skip this step.

This has made my debaffled pipes sound much better. The fiberglass absorbs the valve noises, air velocity noise and resonance of the pipes. Now I have a deeper growl that is just awesome. It costs about $10-15 dollars and works like a charm for me.

Jay313 · 04-15-2008, 08:54 PM

I just love cheap mods. Very clever idea.

BTW, I assume you pulled that piece of PVC out. Right?!

diamond_jim · 04-15-2008, 09:35 PM

Ha ha!

When you slide the new fibrosleeve (I guess that's a good name) in about 5 inches, you can't see it from the back. It just vanishes. Yet it works like a charm. I love the sound now.

diamond_jim · 04-15-2008, 09:37 PM

I had to make two posts on how to do it because you can only include up to 6 images per post.

chinard · 04-15-2008, 10:03 PM

umm.. wont the pvc melt?

diamond_jim · 04-15-2008, 10:07 PM

There is no PVC left in the pipe. You just use the PCV pipe to help form the fiberglass/wire mesh sleeve and then use it as a tool to help slide the fibrosleeve into the exhaust.

If you open the pic below, you'll see the fibrosleeve is pushed in just a little bit so that the camera could still capture some of the details of the sleeve before I pushed it in further. You'll need to push it in further than this. If you look close you can see the wire mesh that is pressing the fiberglass snuggly against the inside of the exhaust.

chinard · 04-15-2008, 10:13 PM

yeah i just found your other thread on this subject which explained some of the missing pieces.
A bit confusing split between 2 threads like that

diamond_jim · 04-15-2008, 10:18 PM

I agree. But it won't let you include more than 6 pics in a single post. Maybe one of the admin peeps can tie them into a single post.

chinard · 04-15-2008, 10:42 PM

pretty sure its per post and not per thread.
I created a thread a while back, stuck 6 images in first post, followed up with second post with another 2 or 3.. all in the same thread.

Jay313 · 04-16-2008, 12:04 AM

I've already got slight tinnitus (ringing ears) from too many concerts as a pup, so I'm kind of leery of overly loud exhausts. But this one is so cool, I almost want to do it just for kicks. How does your sound compare to typical aftermarket pipes? Please rate it for me: Louder, Not as Loud, About the Same?

diamond_jim · 04-16-2008, 07:16 AM

Quote:

Originally Posted by Jay313

I've already got slight tinnitus (ringing ears) from too many concerts as a pup, so I'm kind of leery of overly loud exhausts. But this one is so cool, I almost want to do it just for kicks. How does your sound compare to typical aftermarket pipes? Please rate it for me: Louder, Not as Loud, About the Same?

Regarding volume, it takes the edge off, if that makes any sense. On a 1 to 10 loudness scale with 10 being debaffled and demickey'd, the fibersleeve is about an 8.5 to 9. For me though the sound is much better because cause I don't have all of the higher pitched noises and I guess that is what makes it more tolerable as well. It's hard to explain. I just love the sound so much more.

And thank you Clint for cleaning it up for me. Cool.

diamond_jim · 04-17-2008, 12:20 PM

I've got some of the wire mesh left to make about 6 pairs of precut pieces. I have no use for them now. I can send them to you free if you live in the States. Just PM me your address. You'll have to get the muffler packing though.

old new biker · 04-17-2008, 04:45 PM

This is compelling, as I have been thinking of debaffeling my M, but have been concerned about the harshness of the fully debaffeled sound. This may be what convinces me to go ahead.

PM sent for a pair of the precut pcs.

Question 1) It may be hard to do but can you describe where the new sound lies, using the fully factory baffled M50 and the average Harley, as the extreme limits?

Question 2) I can not even see where the original baffle was. Did you grind out the rough edge, and if so, how did you do it?

BigBlackM50 · 04-17-2008, 05:11 PM

now how well will it stay inside the muffler with just the spring action as your stop? Would you do it if your pipes were only debaffle not demickey.

diamond_jim · 04-17-2008, 05:49 PM

Quote:

Originally Posted by BigBlackM50

now how well will it stay inside the muffler with just the spring action as your stop? Would you do it if your pipes were only debaffle not demickey.

Mine stay in just fine. I had them in for about two weeks and now about 135 miles. I've measured a couple of times after rides from the end of the fibrosleeve to the end of the tail pipe and I haven't noticed and movement at all. I took mine out to take pics for the tutorial and then put my original ones back in. So I haven't had any problems.

Quote:

Originally Posted by old new biker

Question 1) It may be hard to do but can you describe where the new sound lies, using the fully factory baffled M50 and the average Harley, as the extreme limits?

Well, it sounds more like a harley now that it did with just debaffle and demickey. An M50 will never have the same "potato, potato. potato" sound as a harley due to engine design. But it sounds much better, like it's got a bigger motor. Prior to the install, when I'd rev up the bike inside of the garage, it would make me cringe just a bit. It's not really because of the loudness, but because it was kind of a noisy loud. There was this kind of hollow, metally noise mixed in with the lower growl, kind of like a lawn mower and a harley parked next to each other with both running. That's what made me cringe a little bit. But the fibrosleeve seems to absorb the high frequencies and the natural resonance of the exhaust pipe and now I pretty much hear just the growl part. It decreases the volume just a smidge. If you have debaffled and demickey'd and want to go back to the volume of the completely stock pipe, then this will not be the answer. It's almost as loud as before but a much better loud.

And I got your PM. I'll be going by the post office Monday to send them.

Quote:

Originally Posted by old new biker

Question 2) I can not even see where the original baffle was. Did you grind out the rough edge, and if so, how did you do it?

I did the standard debaffle with the double hole saws. There's a great tutorial here: De-baffle this!

old new biker · 04-18-2008, 03:12 PM

Quote:

Originally Posted by diamond_jim

I did the standard debaffle with the double hole saws. There's a great tutorial here: De-baffle this!

Thanks for the link DJ,

I have seen that video several times, and am very familiar with it. My question is regarding the leftover burr all around where the end plate used to be. He does not talk about that in his video.

Your pipes look perfectly smooth and I am wondering exactly how you cleaned up the left over circumferential burr?

I know of several ways, but am just curious how you did it?

Thanks again DJ

diamond_jim · 04-18-2008, 07:36 PM

Actually, I didn't do a single thing to clean them up. I just drilled them out with a hole saw just like in the video. I used new, good quality hole saws. But seriously, what you see is what the saws did. The saws, when set up just like in the video, fit snug enough to keep it from moving around by just loose enough to allow it to spin. It really is an ingenious technique.

diamond_jim · 04-20-2008, 11:02 PM

I did some experimenting on the fibrosleeves today. I pulled them out, did some cruising around town and then put them back in and cruised around town some more. Then got on some open roads and ran her a littler hard. I then took out the fibrosleeves and and ran the open roads again. I'd say the fibrosleeves quiet the debaffled/demickey'd exhaust buy about 25-30% during the points were open pipes are the loudest- WOT, running at steady highway speed and on deceleration from a higher RPM range. The volume at idle sounds about the same. From idle to redline, though, they sound deeper and much better.

Jay313 · 04-21-2008, 09:18 PM

You've got me seriously thinking about it. Basically, what you've done is stuff the insides of an old Cherry Bomb into the stock M muffler. Love it. I think you're probably going to have to repack every year or two, so don't give away all your leftover mesh. I suspect it will start to rust/corrode after a year of temperature extremes in the pipe. But it's so cheap, who cares?

Oh, and I love how you're sticking with your name -- the fibrosleeve. Gotta catch on sooner or later, right?

04-15-2008, 07:39 PM	#1 (permalink)
diamond_jim Refrigerator Magnet Test Engineer Joined: Oct 2007 Bike: S4 Scatcat Location: North Alabama Posts: 3,622	M50 fiberglass rebaffle for low $$$ (merged) Compared to stock, I love the sound of M50 pipes that have been debaffled and demickey'd. However, I've always thought they were a little loud when I accelerated hard and that there was a little bit of a high pitched sound mixed in with the deep growl. Some of that high pitched noise is valve noise and some is resonating from the mufflers themselves. I've wanted all that deep growl but get rid of those higher pitched noises. So after experimenting a lot, I found a low $$$ fix that tames the volume just right and makes for a better, deeper sound. So, here's the tutorial: 1. Get a pack of fiberglass muffler packing used to repack sportbike mufflers. I got this pack for $6.50 at a local bike shop. The piece I got was about 14" x 12" and about 1" thick uncompressed in the bag. 2. Get a piece of masonry wire mesh (used for things like interior rock work around a fireplace, etc). A sheet is about 2'W x 8'L and has a tar paper backing. The wire mesh is pretty stiff and has a great springy action when rolled. I had some laying around. A sheet costs about $5 at Home Depot/Lowe's. 3. Cut two pieces of the wire mesh about 8" long and about 6" wide. I've experimented with several different sizes and lengths so I'm giving you the dimensions of what worked best. 4. Cut two pieces of fiberglass muffler packing about 8" long and about 6" wide. 5. Now find a spray paint can. (use blue paint because we all know that blue is always faster!) Now roll a piece of the wire mesh around the paint can. Be careful to roll it nicely and not force it and cause it to bend. We want to use the spring action that is inherent in a piece of nicely rolled wire mesh. See the accompanying post for the rest of the steps...(just above or below this post, depending on how your posting time/dates are set) Last edited by diamond_jim; 04-16-2008 at 11:01 AM.

04-15-2008, 07:58 PM	#2 (permalink)
diamond_jim Refrigerator Magnet Test Engineer Joined: Oct 2007 Bike: S4 Scatcat Location: North Alabama Posts: 3,622	M50 fiberglass rebaffle part 2 This is part 2 of how to rebaffle M50 stock pipes with fiberglass. See the accompanying post #1 (just above or below this post, depending on how your posting time/dates are set) for the first 5 steps. Continued... 6. Find a piece of 2" PVC pipe that's about 8-10" long. It works better if you have some kind of flange or fitting on one end. I'll explain later. Wow... I just happen to have a piece laying around... 7. Now you are going to roll the wire mesh a little tighter. Roll it nicely around the PVC pipe just like you did on the paint can. 8. Let it overlap about 1/2" and trim off the extra. 9. Now wrap your wire mesh around the PVC again and then wrap the fiberglass muffler packing around the wire mesh and trim it so that it looks like this: The PVC pipe will not remain in the muffler. It is used only to mold the wire mesh shape and as a tool to help place the fiberglass and mesh in the exhaust. 10. While holding the fiberglass/wire mesh tightly around the PVC, slide it into the debaffled pipes. 11. Slide it in several inches. This is were the flange or fitting on the PVC pipe helps to slide the fiberglass,wire mesh in the exhaust pipe. Once in, pull the PVC pipe out. The spring tension in the wire mesh presses outward against the fiberglass and holds it tightly in place. In the above pic, the fiberglass is slid about an inch so that the camera could capture it. Slide it in further than this though. Now do the other pipe the same way. Be sure to use the paint can then PVC to roll the wire mesh. If you go straight to the PVC it's more likely to bend the wire as you try to roll it. Don't skip this step. This has made my debaffled pipes sound much better. The fiberglass absorbs the valve noises, air velocity noise and resonance of the pipes. Now I have a deeper growl that is just awesome. It costs about $10-15 dollars and works like a charm for me. Last edited by diamond_jim; 04-16-2008 at 10:58 AM.

04-15-2008, 10:07 PM	#7 (permalink)
diamond_jim Refrigerator Magnet Test Engineer Joined: Oct 2007 Bike: S4 Scatcat Location: North Alabama Posts: 3,622	There is no PVC left in the pipe. You just use the PCV pipe to help form the fiberglass/wire mesh sleeve and then use it as a tool to help slide the fibrosleeve into the exhaust. If you open the pic below, you'll see the fibrosleeve is pushed in just a little bit so that the camera could still capture some of the details of the sleeve before I pushed it in further. You'll need to push it in further than this. If you look close you can see the wire mesh that is pressing the fiberglass snuggly against the inside of the exhaust. Last edited by diamond_jim; 04-16-2008 at 11:18 AM.

04-20-2008, 11:02 PM	#19 (permalink)
diamond_jim Refrigerator Magnet Test Engineer Joined: Oct 2007 Bike: S4 Scatcat Location: North Alabama Posts: 3,622	I did some experimenting on the fibrosleeves today. I pulled them out, did some cruising around town and then put them back in and cruised around town some more. Then got on some open roads and ran her a littler hard. I then took out the fibrosleeves and and ran the open roads again. I'd say the fibrosleeves quiet the debaffled/demickey'd exhaust buy about 25-30% during the points were open pipes are the loudest- WOT, running at steady highway speed and on deceleration from a higher RPM range. The volume at idle sounds about the same. From idle to redline, though, they sound deeper and much better. __________________ M50 tutorials, tips and how-to links DJ's new project bike Last edited by diamond_jim; 04-20-2008 at 11:04 PM.

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04-15-2008, 08:54 PM	#3 (permalink)
Jay313 Ditch Magnet Joined: Mar 2008 Bike: 07 M50 Limited Location: Dallas Posts: 158	I just love cheap mods. Very clever idea. BTW, I assume you pulled that piece of PVC out. Right?!

04-15-2008, 09:35 PM	#4 (permalink)
diamond_jim Refrigerator Magnet Test Engineer Joined: Oct 2007 Bike: S4 Scatcat Location: North Alabama Posts: 3,622	Ha ha! When you slide the new fibrosleeve (I guess that's a good name) in about 5 inches, you can't see it from the back. It just vanishes. Yet it works like a charm. I love the sound now.

04-15-2008, 09:37 PM	#5 (permalink)
diamond_jim Refrigerator Magnet Test Engineer Joined: Oct 2007 Bike: S4 Scatcat Location: North Alabama Posts: 3,622	I had to make two posts on how to do it because you can only include up to 6 images per post.

04-15-2008, 10:03 PM	#6 (permalink)
chinard In Training Joined: Feb 2008 Bike: '08 suzuki m50 Location: Toronto Posts: 137	umm.. wont the pvc melt?

04-15-2008, 10:13 PM	#8 (permalink)
chinard In Training Joined: Feb 2008 Bike: '08 suzuki m50 Location: Toronto Posts: 137	yeah i just found your other thread on this subject which explained some of the missing pieces. A bit confusing split between 2 threads like that

04-15-2008, 10:18 PM	#9 (permalink)
diamond_jim Refrigerator Magnet Test Engineer Joined: Oct 2007 Bike: S4 Scatcat Location: North Alabama Posts: 3,622	I agree. But it won't let you include more than 6 pics in a single post. Maybe one of the admin peeps can tie them into a single post.

04-15-2008, 10:42 PM	#10 (permalink)
chinard In Training Joined: Feb 2008 Bike: '08 suzuki m50 Location: Toronto Posts: 137	pretty sure its per post and not per thread. I created a thread a while back, stuck 6 images in first post, followed up with second post with another 2 or 3.. all in the same thread.

04-16-2008, 12:04 AM	#11 (permalink)
Jay313 Ditch Magnet Joined: Mar 2008 Bike: 07 M50 Limited Location: Dallas Posts: 158	I've already got slight tinnitus (ringing ears) from too many concerts as a pup, so I'm kind of leery of overly loud exhausts. But this one is so cool, I almost want to do it just for kicks. How does your sound compare to typical aftermarket pipes? Please rate it for me: Louder, Not as Loud, About the Same?

04-17-2008, 12:20 PM	#13 (permalink)
diamond_jim Refrigerator Magnet Test Engineer Joined: Oct 2007 Bike: S4 Scatcat Location: North Alabama Posts: 3,622	I've got some of the wire mesh left to make about 6 pairs of precut pieces. I have no use for them now. I can send them to you free if you live in the States. Just PM me your address. You'll have to get the muffler packing though.

04-17-2008, 05:11 PM	#15 (permalink)
BigBlackM50 Where Am I ? Joined: Feb 2008 Bike: black m50 Location: Minnesota Posts: 25	now how well will it stay inside the muffler with just the spring action as your stop? Would you do it if your pipes were only debaffle not demickey.

04-18-2008, 07:36 PM	#18 (permalink)
diamond_jim Refrigerator Magnet Test Engineer Joined: Oct 2007 Bike: S4 Scatcat Location: North Alabama Posts: 3,622	Actually, I didn't do a single thing to clean them up. I just drilled them out with a hole saw just like in the video. I used new, good quality hole saws. But seriously, what you see is what the saws did. The saws, when set up just like in the video, fit snug enough to keep it from moving around by just loose enough to allow it to spin. It really is an ingenious technique.

04-21-2008, 09:18 PM	#20 (permalink)
Jay313 Ditch Magnet Joined: Mar 2008 Bike: 07 M50 Limited Location: Dallas Posts: 158	You've got me seriously thinking about it. Basically, what you've done is stuff the insides of an old Cherry Bomb into the stock M muffler. Love it. I think you're probably going to have to repack every year or two, so don't give away all your leftover mesh. I suspect it will start to rust/corrode after a year of temperature extremes in the pipe. But it's so cheap, who cares? Oh, and I love how you're sticking with your name -- the fibrosleeve. Gotta catch on sooner or later, right?

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