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Panigaliscious
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Discussion Starter #1
I was thinking about this the other night regarding the changes in motorcycle exhaust design as it relates to differences between stock, absolutely street-legal exhaust systems and aftermarket system of dubious legality.

Perhaps a history summary is in order. In the bad old days of the late 70's and 80's, stock exhaust systems were in a word: crap. Unbelievably heavy and restrictive. This was the first sound and/or exhaust emissions time period, manufacturers basically choked off exiting hot air and with it had to also lean out the carbs to get the engine to run right at the lower power level. This was also the time when aftermarket became popular, I remember my Basaani system on my first streetbike, 1982 GS1100E, weighed at least 25 pounds less than stock. Once a free-flowing exhaust was fitted, get out the drill and put a jet kit in with a K&N filter. Easy 15+ horsepower and the bike ran better to boot.

So sometime around when Clinton took office manufacturers figured out the new rules for exhausts, and were willing to put exotic materials to keep them light as well. Kawasaki was first with a Ti can as OEM IIRC around 1994. Throughout the next 10 years, a tuner might be able to get a few hp with a new exhaust system and jet kit, but mostly it either moved the power around in the rev range or just made more noise. The stock exhaust was already pretty good, if obviously heavier than a full titanium header and CF can combo.

Now fast forward to the last five years or so. Bikes are undoubtedly improved in many ways, but one way they have stagnated is horsepower (stock). In some cases as a new sound maximum takes effect the next model year actually drops in power a bit, as was the case with the CBR600RR and R6. However, something interesting has also been observed. If a full system in replaced and then tuned (using power commander or similar), you are starting to see large gains in at least one part of the rev range.

KR Tuned exhaust boasts a 15+ gain for the CBR1000RR, already no slouch. Motorcyclist had a long-termer that made 170 rwhp. Very impressive, although I don't recall the brand of exhaust.

Anyway, my thought is that current bikes have much more horsepower potential, but ever more restrictive standards are keeping stock horsepower levels in check. Perhaps it is a return to the days of a new exhaust really freeing up many more horsepower.

Just a thought, would like to hear some opinions.
 

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He with the senior member
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I agree with your premise, Burns. The fact is...the EPA regs are forcing huge inefficiencies (in terms of weight and power) on the manufacturers.

The aftermarket systems are not "better." They are actually mostly WORSE in terms of overall performance (power, noise, pollution, longevity) compared to the OE systems, but due to the huge penalty in weight and engine performance that the EPA regs have on manufacturers, the aftermarket systems are able to provide huge increases in power with lighter weight.

BUT...they do not meet the street EPA requirements (other than perhaps some very exotic, expensive, systems....which fall midway in performance between the blatantly street-illegal systems and the OE systems)
 

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Perhaps a history summary is in order. In the bad old days of the late 70's and 80's, stock exhaust systems were in a word: crap. Unbelievably heavy and restrictive.

Just a thought, would like to hear some opinions.
Well if you equate restrictive with dB ratings, then the older exhausts were more efficient than today. Compare the stampings.

The first OEM 4-1 exhaust Honda put on my old '77 CB750F is still one of the best sounding stock exhausts I've ever heard. None of that "puff, puff, whiff, whiff" stuff there.

Adding a performance exhaust to those older bikes had a bigger bang for the buck because the whole engine design was much less efficient per cc than today.

My 2 cents.
 

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As much I love the sound of my Ducati with the half system on it and the sound of a good after market system (Full or Half) I admit my next bike I may not change our the exhaust. While living in CA I was amazed how no one (almost no one) toucht he engine/exhaust and put on Ohlins, Wheels, Brakes, clip ons, rear sets, etc and how these guys just FLEW through the canyons. I got use to a "quiet" bike. Very stealthy and harder for CHP to find us. My next machines I'm thinking I'm going to leave the motor alone and fool around with tasty ohlins bits.
 

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Panigaliscious
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Discussion Starter #7
BUT...they do not meet the street EPA requirements (other than perhaps some very exotic, expensive, systems....which fall midway in performance between the blatantly street-illegal systems and the OE systems)
That should have been clarified in my OP. The stock systems are legal in every sense, while I would guess that basically every aftermarket system is illegal due to some reason be it sound or tailpipe emissions, or likely both. So this isn't really a knock on the manufacturers, I think they are trying to do the best they can with a system that meets requirements (also remember emissions equipment must work for 10? years/80,000 miles or be replaced free) and is cost-effective. Aftermarket can simply put an "Off-Road Use Only" sticker on the exhaust and what the customer does isn't their problem.

I have seen the recent legislation that is pending in CA which will mandate the OEM exhaust after 2013. Riders are up in arms, although all they appear to be doing is enforcing existing federal and state regulations. It will be difficult to fight that one if the governator signs it, IMO. Next step will be to ban the importation into CA of existing bikes with aftermarket exhaust from people moving from other states.

Part of the point I didn't make very well is that the engines today (ignore the exhaust for a minute) have a much higher potential for power than what they display in stock form. With the required stock exhaust they are somewhat corked up and need an (EPA-illegal) aftermarket exhaust to really show what they could do. I would think every literfour made today could put out 200 hp with a few parts and a good tune, although it wouldn't technically be street legal.

Now to the good doctor's point. If you have 150 hp stock, and that isn't enough for you on the street I guess an aftermarket system is needed. I know when I had my Triumph Daytona I never changed the exhaust because with 130 hp it was plenty fast and I didn't wake the neighbors up when coming home at midnight. I never saw the need for more power and kind of liked the quiet exhaust.
 

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Hey sburns,

You had me nodding my head in agreement all the way until I got KR Tuned exhaust boasts a 15+ gain for the CBR1000RR,
I don't know what year that was, But Then, I could Not agree after this, in regards to hp gains in new MC exhaust systems. I have NOT seen Any HP gains in MCs now for well over a year! Not to justify the prices anyhow, 1 to 2hp at the most, with some making LESS tq. even!:eek:
Actually My brother and I have been talking about this for the last year or so, about how much money exhaust systems cost nowadays, with very little to NO gain at all, in either dropping weight and hp., especially compared to the 70s, 80s, and 90s, it's just Friggin" Crazy Mang.! :wacky
I think, as of the last 3+ years, the Japanese OEMs have done a Killer job with their exhaust systems! And I even like alot of the sound quality coming from them as well, (NOT all of them but there's a good few of them, sound amazing:twocents )

Now as far as sound quality goes, I couldn't agree more with fotomoto;
One of My riding brothers has a 1980 CB750 Custom, which is ALL stock, she's got the 4 Ones or is it 4 into 2, 2s into 4 again, it is all original, and, it is in my TOP "3" BEST sounding MCs ever, Especially considering it being 100% Stock!
Now my RC51 I bought brand New, I actually like the OEM exhaust sound "At Idle" (Sounds SO Deep!) better then any after-market system I have heard BUT that's where it ends for Me, as All aftermarket systems sound Better (to Me) at speed or anywhere in the Rev. range on my RC51 and it also seems to (Me) that the V-Twins have better HP performance gains over the inlines regards to aftermarket exhaust systems, Not to mention the OEM V-Twin exhaust system is Killer Heavy compared to after-market.
 

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Panigaliscious
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Discussion Starter #9
The KR Tuned was a claim in an ad from Sport Rider in late 2008, for the then-new CBR1000RR. I'll have to look more closely.

I was actually looking at a relevant issue last night that had a CBR with Bazzaz traction control compared to a 1098R. That CBR also used a complete aftermarket system, Akrapovic IIRC. It was obviously well set up on the dyno by Bazzaz to take advantage of their electrnics modules. The bike didn't have much more peak hp but had big gains of +10 hp or more in the midrange.

The cover picture and dyno run is included here.

Edit: Found a link to the article: Leo Vince exhaust for the Honda in Sport Rider.
Ducati 1098R And Honda CBR1000R - Sport Rider Magazine

This link will take you to the long-termer at Motorcyclist. FMF exhaust. 12 hp on top (169 hp).
Aaron Frank's Honda CBR1000RR - Motorcyclist Magazine
 

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lidzduc.blogspot.com
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1.New motorcycles (litre bikes, at least) are restricted for HP by the computer- mostly for legal, gov't reasons-not from the exhaust.
2.Most exh. systems are changed for "sound" and "weight" only---the former most likely leading the reasoning. The squids will claim the HP factor because- a. they don't know the facts or don't care to know- and\or- b.can brag about the HP increase to their "squidly" buddies.
3. If anyone thinks that the old Honda 750's sound great with the stock exhaust (note: this is the era I grew up in)...they have never heard one with a 4-1 aftermarket pipe of the day--Kerker, Yosh, Jardine, et-al---still the sweetest sounding thing in MC'ing, especially when brought to redline in all gears!:notworthy
Close second- my old Ducati Paso 750 with Cobra F-1 slip on's----NICE!
 

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Panigaliscious
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Discussion Starter #11
1.New motorcycles (litre bikes, at least) are restricted for HP by the computer- mostly for legal, gov't reasons-not from the exhaust.
I'm not sure I agree with this statement. Sportbike manufacturers constantly one-up each other with claims of peak horsepower to lure in the spec sheet buyers. For the Big Four, to be the "it" bike in any given year that every guy and his buddies want is their goal. Of course they know in a model year or maybe two another manufacturer will have something lighter and better handling but most importantly, more powerful. BMW is the newest gottahaveit bike and it makes 30 hp more than some of the Japanese literfours on top.

Every one of the Big Four knew this bike was coming and if it was a matter of a few lines of code their 2011 bikes would all have much more peak hp since getting trumped by the S1000RR. You would also see huge gains from tuning even using stock exhaust, but it doesn't happen.

Evidence seems to suggest that there is not huge amounts of power being intentionally removed from their top sportbikes. Mechanically they are limited through intake and exhaust restrictions and make all they can given their current constraints.
 

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Panigaliscious
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Discussion Starter #13
I saw the post with an old magazine cover and a chart and figured it was Larry. :D
You want a magazine cover? Check this s*** out.

Missouri Sex Slave Appeared on Cover of Fetish Magazine - St. Louis News - Daily RFT
Missouri Sex Slave Kept in Dog Cage, Genitalia Nailed to Board - St. Louis News - Daily RFT

One of the five guys, Stokes, lives less than a mile from me. His wife just retired from the local school system. Bizarre as f***.

If you read the story and all the crazy stuff they did to this girl, it really is amazing there are people like this in the world. The girl worked at a local muffler shop, so she wasn't kept under lock & key. The part where he tattoed a bar code on her neck because he owned her is beyond creepy.

I just hijacked my own thread, maybe I am turning into Larry!
 

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It's your thread Burnsie... At least you post stuff of Interest, debate on an adult level, and toss in boobs and S&M for the cherry on top. Something about seeing Larry in a Gstring wearing repsol gear still gives me nightmares..
 

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Is that Duke Red Enough?
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With all the back to back testing I've done over the years, the solid facts are that OEM exhausts are restrictive, heavy and inefficient.
Fitting a well designed aftermarket exhaust improves engine performance, lowers operating temperatures and improves fuel economy.

We're constantly involved in running battles here in Australia with our EPA regarding the same issues as you guys.
In some states the exhaust must display the OEM stamp; easy enough to circumvent by removing the Termi or Yosh sticker and breaking out the engraver.

It shouldn't come to that though.
The EPA are in a position to advise stupid politicians that restrictive exhausts are "Green" regardless of how heavy they are, how hot they get, how much exotic material is used and how long they take to build.
 

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V4 CyclePath...
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Well I hope history don't repeat itself... some one at HRC took a fork lift and ran
over each RC45 exhaust to crimp down the power and the sound level in order
to comply with our friendly Feds...


 
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