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Discussion Starter · #1 ·
Brought to you courtesy of idle hands and an angle grinder :twisted:

My K4 came with rusted pipes, which have been replaced by David Silvers pattern pipes.

Rather than just throw them away, I thought I'd have a look at the old pipes, see it anything was salvageable. Quite surprised at the internals. I'd expected a conventional system of tubes and baffles, usual labyrinth. Instead, I found that 2/3 of the silencer was empty space, just a straight internal pipe opening into the megaphone section, with a oddly baffled last third of the system, as in these photos.

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Actually it makes sense to me. Honda lengthened the primary pipe to enhance low rpm power with the pipe extension inside. The baffle creates enough back pressure and sound deflection so the sound waves revert back on themselves while expanding. That small hole in the extension pipe is probably to cancel high frequency sound.
 

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Discussion Starter · #3 ·
Just looking inside the DS pattern pipes with a torch (flashlight), they seem quite different internally, certainly don't have that long primary pipe. They also seem quite noiser, certainly louder than I remember the pipes on my first CB175 were.

Be interested to hear from folks who still have OEM pipes on their 175 / 200 s.
 

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Discussion Starter · #4 ·
A couple more photos.

I wish I had Allen Millyards skill. He hand rolls his own expansion chambers and exhausts from stainless steel ( polished up, easier than getting them chromed ). Easy to see how pipes like these could be reskinned by someone like him.

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