I mentioned the other day my concerns over how hot my V85TT (e5) was running with the heat from the cat clearly felt through my boots. So today I fitted a de-cat Y pipe with the standard silencer. As a point of reference I took the bike on an 8 mile ride, keeping to the speed limit with the cat fitted and took a temperature reading with an infrared thermometer. The reading, taken midway along the sump was 119’c. With the de-cat Y pipe fitted I repeated the same ride, trying to ride pretty much the same way. The reading had dropped to 107’c. The bike also felt as though it was pulling better in the mid range but until I get to ride Elaine’s bike (standard) back to back against mine I won’t be able to decide. The sound increase is negligible and certainly will not offend anyone. There is no difference in the throttle response (it still has the lag just past tick over) although I have a Mistral v-boost on order (I have read conflicting reviews of them) which I will try.
Very interested in how it goes as im possibly going to follow the same route 
A difference of 12 degrees then. 
Yes. I imagine there will be a much bigger difference when the bike is ridden hard ? Either way the difference is quite noticeable when stopped at lights etc.
Hi
I have also decated my 85tt, 2019 e4.
I fell the throttle response is better,I have also fitted a BMC air filter
Everything else left standard.Heat and weight wise, I think worthwhile
Elaine and I took both bikes out yesterday and swapped half way. Hers is a 2021 v85tt with 3900 miles on the clock. Mine is a 2022 model with 2000 miles under her belt. We both agree that acceleration is definitely better without the cat’. Also the bike is running noticeably cooler. While the exhaust is slightly louder, it certainly isn’t offensively so. We are now going to de-cat her bike too. The next phase is to fit a Mistral velocity stack and v-boost to mine and again run both bikes back to back and see what difference we find. Both bikes are running standard silencers.
i didn’t find any performance change adding the mistral silencer to the rest of the mistral items (these definitely made a performance change), but it does sound so much better it’s enjoyable accelerating just to hear the sound.
Mistral confirmed by email the total increase in power is about 7hp with all items added but that the silencer didnt increase hp or torque.
Enjoying following the v85s transition, possibly over the winter i may de-cat. V boost fitting will follow with interest as that i may do first 
7hp is a pretty good increase, especially when you look at it as a percentage over standard. Running cooler must be kinder to the engine too!
also seems to have more torque lower down in rev range. about 500rpm lower it will go through town traffic which makes it a bit more relaxed.
Sounds like a result! Looking forward to seeing and comparing the results on our two. 