I've been working to improve the exhaust sound and performance on my 2021 Pure. I first replaced the stock headers with a stainless steel Akrapovic header, which eliminated the catalytic converter and flapper, and I kept the OEM Akra dual muffler. I was hoping this would eliminate what we've been calling the "Cold Start-Up Issue" when the bike revs at high rpms for about 20 seconds as it warms up and then returns to normal rpms. The Akra header gave a significant weight loss, a terrific sound, and a freer exhaust flow, but it exacerbated the cold start-up issue by causing the bike to sputter and die on start-up. I reluctantly put the OEM header back on and tried to accept the sewing machine sound. In the meantime, I ordered the Unit Garage Double Low Pipe Titanium mufflers and a pair of their DB Killer Pros. Received the package today and just finished an easy install, then went for a short test ride. My first impressions: the titanium mufflers are light as feathers and they are beautiful with their exposed welds, in my opinion. I set the DB Killers at 90% open to begin dialing in the sound, and I think it sounds about right - not too loud by any measure, but definitely gives a deeper, more resonant rumble. I was a bit concerned that they mufflers would run hotter and possibly mess with my Unit Garage panniers, but I didn't notice any excessive heat on my short test ride. I'll keep an eye on it, though. And it was a tight fit to avoid interference with my SW-Motech center stand. By re-installing the OEM header with the cat and flapper, it eliminated the sputtering and stalling on start-up, and the mufflers give me a much better sound. Here's are a couple of photos:
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I have the UG full system with the high pipe exhaust, Like you, also started with the headers and the OEM twin exhaust w/o baffles, but never had sputtering or stalling on the cold start, just the higher rev constant noise for those 20-30 seconds.
I like the high pipe looks wise but I think the sound was a bit deeper with the OEM exhaust, without the DB killer is ridiculously loud so I use it with the standard DB killer which chokes the bike a bit compared with the header/OEM setup. However, I love the look of the exposed rear wheel so, high pipe it is for now.
Here’s a sample:
I like the high pipe looks wise but I think the sound was a bit deeper with the OEM exhaust, without the DB killer is ridiculously loud so I use it with the standard DB killer which chokes the bike a bit compared with the header/OEM setup. However, I love the look of the exposed rear wheel so, high pipe it is for now.
Here’s a sample:
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