Ooooh, this debate about aftermarket silencers! And the issues surrounding them.

Reading the latest comments about the 1290 and exhaust issue made me think about this as a bigger topic. I don't really know where it's all heading really. Tell you what, the latest craze for doing up '70's bikes in Cafe racer guise doesn't give a shit about noise regulations or CAT or even performance. It's all down to how it looks!

It seems to me that there are a number of factors on our road going, track able Superdukes.

First the OE silencers have to perform a specific function for sale on a new bike. They have to get through the EU regulations for noise and emissions. The constrictions this enforces on the designers and engineers means that they are not really able to focus on out right horsepower and it is often at the compromise of smooth engine management, especially at low revs and the current SD, as we all know, was a victim of this. Luckily, in the UK, noise is not part of the MOT testing, but that is probably not a realistic vision for the future, certainly now the official rule is that the silencer should have an EC approved stamp on it although this is invariably overlooked at present.

The basic rule is buy a new bike and immediately junk the OE exhaust system for something that is better designed for performance.

Second. All the aftermarket exhausts, full systems and slip-on silencers, are offered to improve horse power and breathability. But it is always at the expense of silencing and maybe fuel efficiency and it is then essential for the carbs or FI system to be adjusted to compensate for the fuel/air mixture. The CAT system is often removed which is great for the bike but less so for the environment although I guess not many people are bothered by this. The down side is that now many of us want to run the bikes at tracks and there is a decibel noise limit which we all want to fall under. So, however much free-breathing power can be gained, we want it to be available at, "track-legal" limits. (and that varies from track to track - the stated limit at Laguna seems ridiculously low!!!)

And then, thirdly - but by no means least, the aesthetics. We all want our exhausts and silencers to look minimal and "Moto-GP" and not like some humongous ugly box strapped to the sides of our bikes.

But all of these three requirements are conflicting for the designers and engineers. It's becoming an impossible task to fulfil all three requirements on a new bike.

I think you just have to take your chances and decide what is right for your riding life. If you don't go on tracks then you can, currently, more or less bolt on anything you want and only risk the police pulling you over for overly loud exhaust and that will be more or less your fault for being loud in the wrong environment. Or you can endeavour to run a performance exhaust that conforms to limited decibel tracks that maybe compromises power. Or you can accept a fooking ugly OE system that plays by EU rules and doesn't let you hear the full sound of that fantastic engine you've just bought.

At present with the current SD I am running a full titanium Akra system that unleashes the full potential of the engine, it looks OK and measures 92 decibels without the baffles so it can run at brands Hatch on their most stringent days. So I guess I have the best of all worlds.

Will it be the same for the 1290? I don't know, we'll have to wait and see. I suspect that 1200cc will be louder and harder to muffle.

For me it has to be an 'aftermarket' exhaust and a map to release the full performance and iron out any flat spots....

That said, if possible it shouldn't be excessively noisy - in my opinion (although my bike is running without baffles at the mo!! I guess you can temper the noise to a certain extent in built up areas)

At least the 1290 has oodles of power on tap.
A remap with the std can, to get rid of any emissions "flat spots" should be enough, especially if you've been riding a wheezy 990 since 05!

I run without baffles all the time. Probably a bit 'anti-social' but I just keep the revs low through towns and urban areas. When I go to the MOT with baffles in the bike just sounds a bit wrapped up in cotton wool sort of sound.

I remember when I had just done up a Ducati SS900 and took it to an MOT centre for the test. I was very apprehensive about the noise levels because it had home made, straight through silencers on it with very little baffling. They guy just fired it up and said, "This is what motorbikes are meant to sound like".

Nuff said, job done.

I think your summary is absolutely right in terms of the options.

What I find so strange is that KTM, and other manufacturers, seem to take the regulations so seriously and yet take a less than conservative approach to marketing. The latter being, by inference, "hooligan" - "ready to race (on the streets)". I don't have a problem with the latter really as it's just hype and those that do will soon be in need of another bike or maybe even dead.

I can't quite understand why KTM don't supply the base bike with a Papier-mâché version of an exhaust knowing full well that the end user will dump it and get something that suits. It seems an anomaly to apparently waste money on providing a can that nobody will use rather than spending the money on better control blocks (if what we've read is correct).

Here in Oz we seem to be lucky in that there don't seem to be restrictions on noise levels at tracks (yet) and the police seem to realise that noisy bikes save lives They really do!!! Forget about Hi-Vis just take the standard can off.

In terms of noise levels I'm not sure what actually makes the noise. Is it just volume or is it the gas exit timing past a restriction? I've heard plenty of big cube engines that are not all that loud. Perhaps if somebody knew the answer to this a quietened straight through system might be possible. Probably not I guess because loud exhausts have been around for a long time.

I run straight through pipes on my bikes. Seems wrong not to on a vtwin.
Initially I was concerned about the neighbours because I do a lot of riding before dawn... until he started his racebike in the shed at 6am on a Sunday morning and I thought it was the apocalypse.
Never been defected.

Looks, weight, sound and regulatory compromises, pretty much makes the exhaust change obligatory.
With a lot of the new bikes you'd swear they had an agreement with the aftermarket manufacturers to make the stock units as hideous as possible.

Does anyone beside Akrapovic make a good full system for the 990SD?
I'm wondering who the likely candidates would be for the 1290 SDR.

Thanks Bic, I often wondered why I didnt keep the, heavy as lead, original exhaust on my bike. I was hitherto putting it down to peer pressure and subliminal Slovakian advertising

Oh yes, thanks Luke, I forgot about the weight thing!

That OE SD silencer is foooooking heavy. I sent mine to NASA to test mass against the anti-matter that they had sourced from a black hole. And it won.

What drives me insane is that you came by a full system for a v8 over here. .. tuned length extractors back full mandrel bent system with x over mid muffler and rear mufflers (a proper twin pipe system). Proper v8 sound, proper performance and good quality for the same price (and less) than the akra system).

Way more meters of tubing, bending, welding, extra components and it costs the same or less than out twin pipe header system. I can justify a grand on a bike system but anymore seems like a complete rip off in comparison.

And they can't even make the damn thing look good. .. seriously. Do they think we are morons... The things are made in third world europe where it is cheap anyway. Why are we ripped so badly?

I don't know the full v8 system, but could the titanium vs iron price have anything to do with it?
And that titanium is harder/ more expensive to process?

I'm surprised that more manufacturers haven't gone the BMW route. Build a "break-in" map that passes import regs then schedule a remap at the first service to unleash the beast. Best of both worlds. Only problem is that once unleashed, it won't pass certain noise tests. And I stand corrected on the 80db limit at Laguna. 80db is the USDOT noise limit. Laguna is 90 db. So, presumably, a bike with an unmodified exhaust should have no problem making the sound limit. However, some stock S1000RRs, Yamaha R6's, Ducatis, RSV4s and Tuonos sometimes fail the noise limit there. Kinda makes you wonder, huh?

I ran a cut and shut system from Austin on my Beemer
On the Dyno it ran 20 bhp down from standard !!!!!

Who da funk it