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Puddle Jumper
Posts: 23
Longmont, CO | When I picked up my Ness Vision, I rode it 1400 miles home. On the first morning while walking up to it I noticed the cross over pipe was damaged by someone in the past. Like it was scraped big time over a curb. It was obviously old damage.
Long story short, I convincingly argued that since it was considered a "new bike" from the dealership and was an "executive demo" from Victory, any damage present would have been caused by Victory and therefore repaired/replaced under warranty.
Don't know what he said to get Victory to get it warrantied but I just received the new pipe in the mail. The thing is the entire rear cylinder exhaust down to both mufflers. Big piece to include the heat shields.
I noticed that there are two "catalysts" in the pipes. At least that's what they are called in the service manual.
Anyone know if they are truly needed? Pros or cons of removing? I'm assuming it's an emissions thing or maybe a back pressure thing.
If it's like a car, would only be good from a performance perspective on removing them.
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Iron Butt
Posts: 935
Rockford, IL | The general consensus is that you are better leaving them in. Takes quite a bit of labor to remove the materials and under most conditions you actually reduce HP by removing them. At least this is what I've read, however I don't believe anyone has posted any dyno information to supoort the theory. |
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Cruiser
Posts: 251
Mechanicsville, VA United States | Leave it in there is my advice, you'll be happier in the long run.......I removed mine just on the left muffler, the most work I've done since I was in my 20's, went through 3- 1/2" drill bits and took about 30 mins........after running the bike I couldn't tell anything in proformance gain just that I'll never remove another one. |
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Visionary
Posts: 1340
Gainesville Fl Home of the Gators | There is no performance gain. Vic uses them as a velocity device, and removing them will reduce low, and mid range torque |
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Tourer
Posts: 466
Grand Cane, LA | I removed both of mine and I will definitely tell you it is a mistake. Like kevinx said, you lose low end torque for sure and any decel popping you might have had will definitely be louder. Ended up buying a whole new headpipe because the catalysts can't be bought separately. |
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Puddle Jumper
Posts: 43
Rossville, IL | I've done quite a bit of experimenting with them both in and removed. If you are running anything except the stock mufflers, definitely leave them in. As others said, you lose a lot of bottom end torque and the popping is definitely worse (and louder).
However....if you happen to be running cams, high compression pistons, head & valve work, rev extend, PCV with auto tune, and the stock mufflers....removing the cats actually improved bottom, mid, and top end power in my particular case and the popping is completely eliminated (or at least very well muffled). While I'm not particularly fond of having a quieter bike, I've grown to accept it in sleeper form now. Twisting the throttle and easily breaking the rear tire loose in first & second leaving a stoplight is way more fun than the wahhhhhhhh_pop!_wahhhhhhh_pop! that I had before.
I'm certainly not advocating that you remove the cats, but with the right mods and using the stock mufflers, there may be a case for it. BTW, if you want your eyes opened, check out Lloyd's website and compare the HP & TQ numbers of the different Vision aftermarket mufflers compared to his big bore kit using a completely stock exhaust system for a "singer sewing machine" quiet ride...137/133 isn't anything to sneeze at and I was astounded that you could get that with stock mufflers. That's what prompted me to go back to them with my mods and I'm certainly glad I did now. |
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