How to make a reverse cone exhaust quieter?

12024 Views 30 Replies 9 Participants Last post by Farmer_John, Oct 3, 2020

pbergmans

Discussion Starter · Sep 22, 2020

Hi all...I recently installed a reverse cone exhaust on my 2017 Yamaha SR400. When I fired it up for the first time I immediately realized that it's too loud. I'm quite sure my neighbors are going to hate me for this mod. My question is, how can I make this exhaust more quiet? I've seen some videos of people adding baffles to their exhaust but in these examples the person had a (more or less) straight pipe and they were able to drill a hole in the pipe to secure the baffle. When I look at my reverse cone, I don't really understand how I can do that. I'd also like to add that I'm a newbie at making modifications and I don't have any fabrication skills. So, if you have a suggestion for me, it'd be best if I could buy something that's semi-easy to install. Here is an image of my exhaust...

Thanks in advance.

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pbergmans

Discussion Starter · #4 · Sep 22, 2020

Hi @TrialsRider ... thanks so much for your response and the heads up regarding the emission controls. I'll look into my state's laws requiring catalytic converters. I'm still learning so I have a few questions for you:

1. If a catalytic converter is required (by most localities I assume), what do most people do in regards to modifying their exhaust? My stock exhaust is too dorky looking and I'm trying to go for a more cafe racer look.
2. If I bought the wrong exhaust, what should I have purchased that would still allow me to have the reverse cone look?
3. If I can successfully remove the rivets, are suggesting that I might be able to re-pack the inside with more fiberglass (or whatever the material is)?

Thanks again.

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pbergmans

Discussion Starter · #9 · Sep 22, 2020

@jcw - thanks for the useful information. Am I right in thinking that your comment "and mount with a set screw from the outside" is not easily possible since I have a cone? Or, do I disassemble my exhaust (e.g. remove rivets) and replace the core? Do baffles exist that have a different mounting mechanism other than an external screw? Or, is welding it in my only solution?

@TrialsRider - thanks for the information, I certainly learned more about exhaust from your few comments and, in a way, wished I had known this info prior to purchasing my shorty reverse cone. I guess I was just excited to get moving on my mods. But, with that said, what is one to do if they want to modify the exhaust on their motorcycle? After all, isn't that the reason why some of us have joined this forum? Heck, even the picture at the top of this page has three motorcycles with custom exhausts? Do the exhausts on these three bikes have catalytic converters.

Can anyone recommend a "cafe racer" style exhaust that meets emissions laws?

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pbergmans

Discussion Starter · #13 · Sep 22, 2020

@TrialsRider - it's my first bike so I have nothing to compare it to. I bought it because it seemed like I could modify it into a cafe racer given my limited skillset. It was also relatively new so it would be more reliable versus a more classic bike from the 70s or 80's. I'm not much of a speedster either so the single cylinder is fine for now. I could see myself bumping up to ~650cc in the future but I want to successfully convert this bike first.

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pbergmans

Discussion Starter · #26 · Sep 24, 2020

All..thanks to everyone that has replied. You've given me a lot of helpful information! Attached are some pictures of the inside of the exhaust. It looks like it's a straight through shot from end-to-end. It looks like the inside material has some texture to it but it doesn't have holes/mesh (it's more ribbed).

I wanted to check back with all of you before removing the rivets. Does it look like I can make modifications to what I've got to make my exhaust more quiet? Or, am I SOL and should I bite the bullet and get another exhaust.

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