I believe these are made for HD's "only", but can be installed on any bike. In looking at them, it appears they are concave, not flat. Anyone here tried them?
Supposed to let you tune your exhaust for torgue and deepen the sound.
Had never heard of them before, so thanks for the educational push.
It appears to me that they primarily restrict the exhaust flow and this is how they increase the torque.
In reality, they are increasing the back pressure of what was a free flowing exhaust system.
There was a misconception for years, that an open exhaust was better for performance, simply because it was louder. In actuality, they were giving up torque at lower rpm's to gain that sound.
If you have an original exhaust on your bike, it's already pretty restrictive at the tea pot spout.
If you have something like the V&H, then yes, it might make a difference.