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General Category => General Discussion => Topic started by: JHBettsSr on May 30, 2026, 12:32:50 PM
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Have any of you folks done a Decat on your '24-up E5+ V85's? I'm looking at Mistral or QD for options. If you have any experience or recommendations, please share. Thanks very much.
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I used the cheap 19-23 Chinese one on my 25. It works fine but the 25 stock muffler goes on the outside of it instead of the inside. Best to use an earlier one but you don’t have to. I posted pics a while back here or on ADVRider.
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I bit the bullet and ordered the E5+ (no-cat) system from Mistral in Italy. Hopefully those loafer wearing, chain smoking, guys at Mistral will put down their coffee long enough to ship it soon :-).
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Yike$!! I m glad I got mine when I did. I got the version with the cat as I wasn’t sure if the non cat would change the tune that much. Its in the pipe and not even noticable. Did you also get the V twin boost? If not how do you plan to retune if its changed for the worse?
Pete
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Yike$!! I m glad I got mine when I did. I got the version with the cat as I wasn’t sure if the non cat would change the tune that much. Its in the pipe and not even noticable. Did you also get the V twin boost? If not how do you plan to retune if its changed for the worse?
Pete
I didn't want the Mistral version with a cat, my plan was to eliminate the cat, use the stock muffler, decrease weight and heat, and get a deeper exhaust tone. I also decatted my '17 Triumph Bonneville T120 the same way and couldn't be happier. I don't plan to retune the V85TT, there are no sensors in or after the cat so the ECU can adapt if it wants/needs to.
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Keep us posted on the results. I replaced the muffler with a Leo Vince just the hear the motor but it saves even more weight too. The cat version just adds wire mesh across the bore at the exit. Probably only accounts for a few ounces vs the non cat version and easily removed.
Pete
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Keep us posted on the results. I replaced the muffler with a Leo Vince just the hear the motor but it saves even more weight too. The cat version just adds wire mesh across the bore at the exit. Probably only accounts for a few ounces vs the non cat version and easily removed.
Pete
Will do, PeteS.
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Small word-bigger bike: I just posted a similar thread on the new Stelvios. Im thinking about de-cating it to lose some heat that it throws, a few lbs and maybe a little better acceleration.
Do you know if just removing the cat and adding the new pipes but keeping everything else stock (ECU and tailpipe) has any other improvements?
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Small word-bigger bike: I just posted a similar thread on the new Stelvios. Im thinking about de-cating it to lose some heat that it throws, a few lbs and maybe a little better acceleration.
Do you know if just removing the cat and adding the new pipes but keeping everything else stock (ECU and tailpipe) has any other improvements?
I can't advise you about your Stelvio and I haven't decatted my '25 V85TT yet (parts are on order). I can tell you that I did decat my '17 Triumph Bonneville T120, kept the stock mufflers, and did not retune anything. The result is much less weight, much less heat coming from where the cat was, and a nice deep, but not loud, exhaust tone. The Triumph may be faster now, it sounds faster anyway, but that's subjective as I did not measure the performance before or after. I'm hoping to get similar results from decatting the V85TT.
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Small word-bigger bike: I just posted a similar thread on the new Stelvios. Im thinking about de-cating it to lose some heat that it throws, a few lbs and maybe a little better acceleration.
Do you know if just removing the cat and adding the new pipes but keeping everything else stock (ECU and tailpipe) has any other improvements?
Check out the Mistral website. They have dyno charts showing before and after installing their exhausts. Gains are minimal, maybe 3-4 hp at best.
Pete
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I didn't want the Mistral version with a cat, my plan was to eliminate the cat, use the stock muffler, decrease weight and heat, and get a deeper exhaust tone. I also decatted my '17 Triumph Bonneville T120 the same way and couldn't be happier. I don't plan to retune the V85TT, there are no sensors in or after the cat so the ECU can adapt if it wants/needs to.
I have a '23 Euro 5 version. The muffler looks similar if not the same as the 5+ and weighs about a ton and a half by itself. :wink: I doubt you'll lose much weight staying with the stock muffler.
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I have a '23 Euro 5 version. The muffler looks similar if not the same as the 5+ and weighs about a ton and a half by itself. :wink: I doubt you'll lose much weight staying with the stock muffler.
That's a good point. I'm aware that eliminating the cat will only cut a few pounds of weight. It's mainly heat from the cat (directly under the oil sump) that I want to be rid of. A deeper exhaust note and easier access to the oil and gearbox drains will be added benefits as well. I'm pretty happy with the weight of the V85TT as is, it's tons lighter than my BMW K1600GT and about the same as my Triumph Bonneville T120.
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And, of course, the O2 sensor only works for you in closed loop mode.
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And, of course, the O2 sensor only works for you in closed loop mode.
The E5+ V85s don’t have a sensor after the cat, only before.
Pete
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Here's an update on the 2025 V85TT Mistral Decat exhaust system. I used Mistral P/N "MG-HP/V85TT-E5+" and I reused the OEM silencer/muffler. The new exhaust headers and Y-Pipe are about 10 lbs less than the OEM. The sound is a bit deeper but not noticeably louder. Here are some before and after images:
(https://i.ibb.co/xtbbJYQj/Y-Pipes.jpg) (https://ibb.co/xtbbJYQj)
(https://i.ibb.co/LDnztd2h/RFront.jpg) (https://ibb.co/LDnztd2h)
(https://i.ibb.co/FbVFqnS6/LFront.jpg) (https://ibb.co/FbVFqnS6)
(https://i.ibb.co/CpWQ25wK/RH.jpg) (https://ibb.co/CpWQ25wK)
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Shout out to the Arrow headers. They use the straps to connect the upper guard and not the welded bungs so I left off the upper guard as I don't need to protect from the ubber hot cat which leaves a nice clean look. They have a beautiful bronze patina.
(https://i.ibb.co/LXCNtgKc/arrow-header.jpg) (https://ibb.co/LXCNtgKc)
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Shout out to the Arrow headers. They use the straps to connect the upper guard and not the welded bungs so I left off the upper guard as I don't need to protect from the ubber hot cat which leaves a nice clean look. They have a beautiful bronze patina.
(https://i.ibb.co/LXCNtgKc/arrow-header.jpg) (https://ibb.co/LXCNtgKc)
Mine is a 2025 E5+. Does Arrow make these for the 2024-up E5+? The image in you photo has the O2 sensors in a pre-2024 location. I couldn't find any 2024-up E5+ Decat systems except at Mistral.
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not sure about the newer tt's mines a 2022.
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Full Mistral system with the Mistral "sport" cat just before the back box. 10kg saving.
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not sure about the newer tt's mines a 2022.
If yours is a 2022 that should make it an E5, not an E5+. I think E5 was produced in 2021-2023.
E5 & E5+ have different O2 sensor locations, and the mufflers connect to the Y-Pipes differently.
I wish Arrow had an E5+ system, the Mistral was $$$$.
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Interesting that yours which doesn’t have a cat has the bung for a sensor but mine with a cat has no bung.
I guess I was fortunate to have ordered mine two years ago from AF1 and price was about half of the current price they have posted now.
FWIW if you decide to replace the muffler, anyones replacement that works with the stock exhaust will work with the Mistral pipe. My Leo Vince slipped right on.
(https://i.ibb.co/RTYKztWP/IMG-1418.jpg) (https://ibb.co/RTYKztWP)
Pete
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Interesting that yours which doesn’t have a cat has the bung for a sensor but mine with a cat has no bung.
I guess I was fortunate to have ordered mine two years ago from AF1 and price was about half of the current price they have posted now.
FWIW if you decide to replace the muffler, anyones replacement that works with the stock exhaust will work with the Mistral pipe. My Leo Vince slipped right on.
(https://i.ibb.co/RTYKztWP/IMG-1418.jpg) (https://ibb.co/RTYKztWP)
Pete
My 2025 doesn't have a 3rd "after cat" O2 sensor. I used a 12 x 1.25mm stainless steel plug and copper washer to fill the Mistral "after cat" O2 sensor hole. It's my understanding that E5+ will eventually monitor exhaust "after cat" to measure catalytic converter performance. Maybe Mistral consolidated part numbers by adding this "after cat" O2 sensor hole for future V85's that may come with an "after cat" O2 sensor?
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FWIW if you decide to replace the muffler, anyones replacement that works with the stock exhaust will work with the Mistral pipe. My Leo Vince slipped right on.
(https://i.ibb.co/RTYKztWP/IMG-1418.jpg) (https://ibb.co/RTYKztWP)
Pete
That's good to know. The Y-Pipe outlets look very different.
(https://i.ibb.co/q3rb24z0/V85-TT-Exhaust-Outlets.jpg) (https://ibb.co/q3rb24z0)
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My 2025 doesn't have a 3rd "after cat" O2 sensor. I used a 12 x 1.25mm stainless steel plug and copper washer to fill the Mistral "after cat" O2 sensor hole. It's my understanding that E5+ will eventually monitor exhaust "after cat" to measure catalytic converter performance. Maybe Mistral consolidated part numbers by adding this "after cat" O2 sensor hole for future V85's that may come with an "after cat" O2 sensor?
US "E5+" (2024+) bikes only have 2 sensors. European E5+ have the full complement of 3 sensors.
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US "E5+" (2024+) bikes only have 2 sensors. European E5+ have the full complement of 3 sensors.
Thanks Kildareman, your info syncs with the email I received today from Mistral. To install the Mistral exhaust on my US E5+ I had to make a plug for the 3rd O2 sensor by cutting a stainless steel bolt to length and fitting it with a copper crush washer. The Mistral exhaust kit I received also included an OBD Device "electrical dongle" to prevent the MIL light from illuminating due to the absence of a 3rd "after cat" O2 sensor. In their email, Mistral confirmed that for the US market they will begin eliminating the electrical OBD device and adding a plug for the 3rd O2 "after cat" sensor hole. Here is an image of their OBD Device "dongle":
(https://i.ibb.co/xqq7pwsJ/OBD-Device.jpg) (https://ibb.co/xqq7pwsJ)
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Here's an update on the 2025 V85TT E5+ Decat. I used Mistral P/N "MG-HP/V85TT-E5+" and reused the OEM silencer/muffler. After a few thousand miles of city rides, twisty backcountry rides and some Interstate/highway miles, I can report a noticeable increase in mid-range power (at around 2,500-4,500 RPM). The power increase is very evident, now when in "Road" mode, it feels more like it's in "Sport" mode. The exhaust note is a bit deeper at idle, but not much louder otherwise. The new Mistral header colors had a silvery "brushed stainless" color. After a few heat cycles they have reverted to the original "bronze patina" color. The Mistral system was a bit expensive, but weight savings, a decrease in heat output, plus increased performance, were worth every dollar to me.
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I had the increased performance on my 2020 with the mistral y pipe. Less heat and increased performance is a rare combo and I kept the stock muffler and the machine sounded better.