Enhance exhaust sound?

[Winston001]

Just curious. Its easy enough to transform a quiet stock exhaust to a loud pipe - just keep cutting and drilling.

But some of the aftermarket pipes do produce a nice note. I've always liked the whistle from Norton reverse-cone pipes for example. And carbon fibre pipes have an excellent crackle.

Anyone tried modifications to stock or bog standard pipes to get a more interesting note? I was thinking steel banding ribbon would vibrate interestingly.....

[steelestring]

Tool: Steel rod ramming baffles... makes a rattleing and a whisle sound at the same time...
Sound: kinda like massy grey as a male going through pubity

Tool: Me

the end

[Winston001]

Tool: Steel rod ramming baffles... makes a rattleing and a whisle sound at the same time...
Sound: kinda like massy grey as a male going through pubity

Tool: Me

the end

Er...as in a Massey Ferguson....??

[Hitcher]

Letting the spokes in your front wheel thrum against a playing card taped to the front forks sounds pretty neat as well.

[monkeymcbean]

Letting the spokes in your front wheel thrum against a playing card taped to the front forks sounds pretty neat as well.

Thats so 'boy racer'!

[vifferman]

I drilled out the central baffle on my VFR750. The zorst gases usually come up, through a restriction (for back pressure wave?) through a tube inthe muffler to the end cap, back down another tube again to the baffle, then back up to the outlet. With the hole (about 20mm), they mostly went through the hold in the baffle plate and out the outlet.
Was very slightly louder'n stock, and not very wonderful.

With the FahrtSturm, some Evildoer/PreviousOwner-cum-Wrecker had cut the end caps out with a 2" holesaw. It was loud, of the "see which parked cars have alarms and feel embrassed coz EVERYONE turns around to see who's coming down the street" kinda loud.

IMHO (and not just based on this unscientific statistical example), home-baked zorsts are generally pooh, from both the performance and auditory standpoint. Sometimes 'professionally' modified OEM zorsts work out OK (although that's doubtful in today's culture) but generally it's worth investing in decent aftermarket stuff that's proven to sound/perform OK.

[Winston001]

Understood Viff. I have a spare set of Ducati mufflers which were drilled out internally. That allowed some of the gases to escape unimpeded but as you say, didn't make a lot of difference.

So......I had an engineer cut slots in the end-caps. Ohhhh YES Now the bike sounds like a Ducati. In fact its a tad too loud. In hindsight I should have simply drilled a couple of holes and experimented. I'll either block one slot or restrict the main pipe to dampen it down a bit.

Still - I'm sure there are simple ways to change the exhaust note. After all, its simply gas pressure. For example imagine a really big saxaphone mouthpiece attached to the end.

[vifferman]

Understood Viff. I have a spare set of Ducati mufflers which were drilled out internally. That allowed some of the gases to escape unimpeded but as you say, didn't make a lot of difference.

How about changing the baffle tube(s) in them? There's not a lot of difference in the construction of various brands of aftermarket mufflers. Apart from the thickness of the external casing, it all comes down to the size, and thickness of the baffles, and the kind of holes in them. After that, the packing and end cap make the final tuning.
Interestingly (or perhaps not), the Satantune used to be quite raspy when sans restrictor. In the last year, I suspect some of the 'permanent' stainless steel wool packing has ... evaporated(?), as it got a bit louder, even with the restrictor in place. As of late (last couple of weeks), the tone is much more bassy than it used to be, so much so that I've been looking for (and not finding) leaks. If they adopt much more of a bass note, I'll probably have to resort to the 'stealth mode' restrictor.
The Satantune is (or rather, 'was') noticeably higher-pitched in tone than other brands, such as Remus, Micron, etc., and I think this is due to two factors: smaller can volume, coupled with the use of 'permanent' packing as opposed to the fibreglass packing favoured by most manufacturers.

I had some custom megaphone-style mufflers made for my VF500 when I lived in Chch. All I specified was that they be s/steel, and a bit louder'n stock. They were basically a simple megaphone shape, with a single perforated core, and (supposedly) matting wrapped around that. I was told I could make'm louder by varying this.
Unfortunately (?) they actually omitted to put any packing in at all, or so I found when I removed an end cap.

Does this get us anywhere?
Um... if you want a better tone, aim for a larger diameter internal core, then tune it as appropriate via end cap restriction. The Satantune has a core that's about 50mm, and I can tone that down with restrictors with internal diameter of around 20mm, and length of ~50mm or ~80mm (for the quiet one). End caps / restrictors are cheap to make. For the de-endcapped FahrtSturm, I had Woolf Muffler make me some and then just kept cutting bits off the internal part of the inner pipe until the volume was just right.

[slofox]

Letting the spokes in your front wheel thrum against a playing card taped to the front forks sounds pretty neat as well.

Topsy stick works much more betterer Hitch...

[NighthawkNZ:Me]

I did a bafflectomy on my VTR quite easily ... it was border line and around 96-98db when I finished, and nice deep v-twin sound... but do need to know the ins and outs of the pipe...

[CookMySock]

I tried drilling a standard muffler, and sounded like it had a farty noisy hole in it. Yuck. I welded it back up.

Buy an aftermarket one. Massive difference.

Steve