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E: Engine Exhaust butterfly valve?

Comet Rider

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VOC Member
Before wrecking the silencer, I would be inclined to experiment on a plain extension pipe. The grass track sidecar guys put four slots in. They didn't remove the piece between the slots, they drove it inwards so it was visible from the end view. It won't make it much quieter but will take the"crack" out of it.
I think you are talking about a Decibel killer.
You can get them as units which insert into the tailpipe



roy the mechanic

Well Known and Active Website User
VOC Member
Decibel killers (also known as mutes) will make the motor just sound sick. I'd stick with the slots.


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VOC Member
VOC Forum Administrator
VOC Forum Moderator
There was a guy in Northern California that had 2” pipes on his Shadow. He had flat discs with tabs. The tabs were bent 90 degrees to the flat disc, and long enough so that the disc could be mounted a short distance away from the end of the exhaust pipes, by clamping the tabs to the pipe. I don’t recall whether or not a small hole was drilled in the flat plate. Similar results to the device Roy mentioned, it was enough to take the bark out of the noise.

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