Yamaha Super Tenere OEM Muffler Mods

prowlnS10

2014 ES
Joined
Jul 13, 2018
Messages
69
Location
Vancouver, BC, Canada
The OEM tailpipe assembly unbolts allowing removal & access to the rear muffler chamber

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My 1st mod was to remove the restrictive spark arrestor assembly that forced gasses to change direction multiple times, reusing the screen over the exposed tail pipe.

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This muffler mod w/oem air filter + Arrow header (no cat) produced the following result on my 2014 after dyno/flash tuning by Nels at 2WheelDynoWorks in Seattle....which he said almost matched a full system with Arrow header & Yoshimura RS4 Muffler.

S10 Tweak DynoFlash Tune June 03, 2016.jpg

My 2nd muffler mod a year later was to make a 1.75" diameter tailpipe assembly vs the oem 1.5"...this resulted in a slightly deeper/louder tone & crisper throttle response. I had a muffle shop custom bend a 7" length of 1.75" exhaust pipe to match the oem bend...they even fluted the inside end to match the oem...then made a mounting plate from 1/8" steel plate, welded them together & painted with extreme heat header paint....the oem spark arrestor screen can be reattached to the larger tailpipe.

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It took a little fidgeting to match the oem angled outlet pipe & tapered terminus of the outlet pipe so that it would fit centered in the angled plastic cover. The muffler shop flared the outlet end before I could stop them...it was not require & decreased clearances to the plastic cover.

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Had to slightly widen the 2 oem mounting plates to accommodate the extra width of the pipe.

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The overall result is a slightly deeper, more robust exhaust note (particularly at idle), while still being touring friendly & quieter than most aftermarket mufflers....combined with oem durability & never requiring repacking...for me weight savings from an aftermarket pipe on a 600+lb low output beast like the S10 is negligible & a mute point IMHO.
 
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Mak10

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Aug 20, 2018
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I fiddled around doing the same thing. Then I broke down and bought a Delkevik 14”. Not much money, sounds great, not too loud, and weighs a lot less. If you like experimenting and tinkering it is fun. Cost wise you would be farther ahead with many more advantages with the Delkevik.
 

prowlnS10

2014 ES
Joined
Jul 13, 2018
Messages
69
Location
Vancouver, BC, Canada
I fiddled around doing the same thing. Then I broke down and bought a Delkevik 14”. Not much money, sounds great, not too loud, and weighs a lot less. If you like experimenting and tinkering it is fun. Cost wise you would be farther ahead with many more advantages with the Delkevik.
Yup...I like to tinker & tweak...total cost only about $35. As per Delkevik advantages...mostly weight (4-6 lb typical range) of which the benefit on a 600+lb bike is negligible...the dyno tune already proved very little gain from aftermarket (within 1-2 hp of an Arrow/Yoshimura combo) vs my modded oem muffler & it retained the enormous low & mid torque curve which sometimes gets moved up the rpm band with aftermarket pipes + never have to repack & the oem will last the life of the bike. The money saved not buying an aftermarket pipe was spent on the Unifilter NU6235 Dual Stage air filter kit ($100 oem fitment in Australia) which provides more benefit than any muffler & the Arrow Header ($296). The S10 really benefits from increased air velocity, particularly at low rpm which becomes buttery smooth & responsive. After a dyno tune/ecu flash removing the oem restrictions in the 1st 3 gears <5,500 rpm & correcting the lean fueling, improved air filtration & decatting (Arrow Header) are the next most beneficial & impactful motor mods on the S10 :) To put things in perspective, the engine tweak mods I have made combined cost less than an Akrapovic muffler! Akrapovic advertises 1.2 hp & 1.4 lb ft gain & 4.4 lb lighter, which are typical of most aftermarket mufflers on the S10.
 

Don in Lodi

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Did you rewrap any sort of spark arresting mesh back on? I saw you did with your 1.0, just no picture if you did the same with your 2.0 mod.
 

STenitus

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Feb 21, 2015
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Alabama
Very cool! I'm curious to know what the muffler shop charged you after all was said and done.
 

richarddacat

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Jan 27, 2015
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574
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Tennessee
I’d be willing to pay you for a 1.75" diameter tailpipe assembly if you cared about making a few for sale?

What would you expect/guess by doing just the spark arrestor removal with the stock tailpiece as far as sound and performance improvements?
 
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ballisticexchris

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Wow what a hell of a modification. And only a 25 horsepower loss at 3500RPM! I do appreciate the dyno numbers though. Your horsepower and torque have a nice curve. But your stoichiometric air fuel ratio is lean. When I had my 650R dyno tuned I made sure that the AF ratio was at least close to 15:1. Ideal is 14.7:1. You are running under 14:1 which is a bit lean. But I do understand it gives you the most HP. Your dyno tuner did a very nice job!!

I have been down this road before on my XR650R. By opening up the exhaust and air box it screamed and howled at high RPM. Unfortunately it fell on its face at trail riding speeds.

Same deal with my KTM300. Big carb and low compression head. It was a monster in the desert but near impossible to ride on single track.

I simply bolted on a Yoshimura can on mine. It's still quiet and still has a very nice flat powerband. How loud is the exhaust modification?
 

prowlnS10

2014 ES
Joined
Jul 13, 2018
Messages
69
Location
Vancouver, BC, Canada
I’d be willing to pay you for a 1.75" diameter tailpipe assembly if you cared about making a few for sale?

What would you expect/guess by doing just the spark arrestor removal with the stock tailpiece as far as sound and performance improvements?
Sorry, not up for doing a production run....but it is relatively easy to make...the muffler shop made the pipe & my brother-in-law did the welding, so all I really did was make the mounting plate & sort out the correct angle of the tailpipe relative to the mounting plate.

The change in sound with spark arrestor assembly removed from the oem tailpipe was just a slight deepening of the sound/volume increase while retaining a mostly oem sound/characteristic...it was subtle...hard to quantify improvement in flow relating to just that change because the dyno run included the Arrow header, but my set-up came close to matching a full system & since most aftermarket mufflers only produce 1 to 3 hp gain anyways on the S10, any improvement in flow was a positive, imho. The spark arrestor assembly caused the flow to change directions multiple times before being able to exit. Based on what I've learnt about how the S10 responds to increased air velocity, particularly at low rpm, there is likely more benefit <4k rpm in terms of responsiveness than max output at redline.

I was surprised that adding the Arrow header didn't increase sound level output more (likely because the 2 chamber oem muffler was retained vs a straight thru pipe)...the change was more to the tone & robustness...being slightly deeper & fuller. The change to the 1.75" tailpipe provided more change than just removing the spark arrestor from the oem tailpipe did & augmented the Arrow sound slightly while adding a little more authority & snarl in the upper rpms ...so it must be flowing more :)

This setup is quieter than most aftermarket mufflers with db killers out & similar in loudness with them in....it's the character of the sound that differs more than volume, with my set up being just a more robust oem character. Hope that helps. I tried before & after recordings, but the difference does not come thru noticeably on my phone...but is apparent to the ear.
 

prowlnS10

2014 ES
Joined
Jul 13, 2018
Messages
69
Location
Vancouver, BC, Canada
Wow what a hell of a modification. And only a 25 horsepower loss at 3500RPM! I do appreciate the dyno numbers though. Your horsepower and torque have a nice curve. But your stoichiometric air fuel ratio is lean. When I had my 650R dyno tuned I made sure that the AF ratio was at least close to 15:1. Ideal is 14.7:1. You are running under 14:1 which is a bit lean. But I do understand it gives you the most HP. Your dyno tuner did a very nice job!!

I have been down this road before on my XR650R. By opening up the exhaust and air box it screamed and howled at high RPM. Unfortunately it fell on its face at trail riding speeds.

Same deal with my KTM300. Big carb and low compression head. It was a monster in the desert but near impossible to ride on single track.

I simply bolted on a Yoshimura can on mine. It's still quiet and still has a very nice flat powerband. How loud is the exhaust modification?
It was originally a little lean somewhere in the 14's with a few areas spiking around 15:1..so we did fatten it up a little & smooth out the <5k rpm curve in the final tune, which made it feel more refined..the current fueling is exemplary! See post #11 above for sound output.
 
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SkunkWorks

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Sep 13, 2018
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Colorado
Wow what a hell of a modification. And only a 25 horsepower loss at 3500RPM! I do appreciate the dyno numbers though. Your horsepower and torque have a nice curve. But your stoichiometric air fuel ratio is lean. When I had my 650R dyno tuned I made sure that the AF ratio was at least close to 15:1. Ideal is 14.7:1. You are running under 14:1 which is a bit lean. But I do understand it gives you the most HP. Your dyno tuner did a very nice job!!
I am sorta confused by this post?
Running an engine with an AF ratio around 15:1 is way too lean......... The higher the number, the leaner it is.
With Gasoline, they say ideal AF is 14.7:1, but engines don't really run very efficiently that lean. When tuning an engine on a Dyno, the most power is typically made with an AF somewhere between 13.0-13.5:1 (naturally aspirated). If you are down around 12.0 it is too rich.
The "Red Dotted Line" on the Dyno graph is usually where the ideal ratio likes to be. As you can see on this pull his AF-ratio is pretty much spot-on.
I would say the tune is really good, and right where it needs to be.
 
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ballisticexchris

Guest
OOPS!! My bad I got it backwards!! Still, he has an excellent tune. To get that kind of ratio is pretty expensive. Lots of dyno time and very fine tuning to get it that good.
 
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