Post by 90GTVert on Apr 12, 2010 20:32:07 GMT -5
This information was provided by 190mech.
In an effort to reduce the noise of my scoot I researched the subject and found a bit in Gorden Jennings book that stated;
Anyway, I gave the scheme a try, and while certain other modifications prevented drawing any absolute conclusions from the experiment, the bike did prove to be very fast, and it seemed certain that while my “inside stingers” might not offer any real power advantage, they probably were at least as effective as those attached in the more conventional manner. But that is not to say that I did not notice a difference - and the difference was in sound. With those inside outlet pipes, the typical expansion chamber crackle was very noticeably subdued. That made sense, as the chambers' outlet to atmosphere was taken from a point where the pulse was at its lowest amplitude - rather than from the high-pressure area at the tip of the baffle-cone.
So I cut off my existing stinger(outlet pipe) and glass packed muffler to see if this would work.Also wanted to add a muffler that I used in the 70's on our woods bikes that proved itself then;
Here is the new outlet pipe(stinger) beside the baffle cone;
The stinger welded inside the baffle cone;
Fabbed a can to enclose the baffle cone;
Built the baffle assembly;
And here is the final product,kinda ugly but nice and quiet at lower revs;
Here is a before and after vid sample,quieter with no power loss;
In an effort to reduce the noise of my scoot I researched the subject and found a bit in Gorden Jennings book that stated;
Anyway, I gave the scheme a try, and while certain other modifications prevented drawing any absolute conclusions from the experiment, the bike did prove to be very fast, and it seemed certain that while my “inside stingers” might not offer any real power advantage, they probably were at least as effective as those attached in the more conventional manner. But that is not to say that I did not notice a difference - and the difference was in sound. With those inside outlet pipes, the typical expansion chamber crackle was very noticeably subdued. That made sense, as the chambers' outlet to atmosphere was taken from a point where the pulse was at its lowest amplitude - rather than from the high-pressure area at the tip of the baffle-cone.
So I cut off my existing stinger(outlet pipe) and glass packed muffler to see if this would work.Also wanted to add a muffler that I used in the 70's on our woods bikes that proved itself then;
Here is the new outlet pipe(stinger) beside the baffle cone;
The stinger welded inside the baffle cone;
Fabbed a can to enclose the baffle cone;
Built the baffle assembly;
And here is the final product,kinda ugly but nice and quiet at lower revs;
Here is a before and after vid sample,quieter with no power loss;