[Pittenger5]

My pipe is colored to match my bike

[ChR1s]

The more you drive, the less intelligent you are.

Conversely, the more you ride...

[ZX-12R]

Originally Posted by taxonomy

I can't imagine a ceiling of 150 HP. I can't imagine needing more HP, more crispness, more anything than is delivered on any stock sportbike over 600cc made after 2000.

You can't truely have fun on a motorcycle unless you have at least 160 at the rear wheel.





But in all seriousness, what the 150+ HP bikes do very well is make substantial horsepower without having to wind the engine up to ungodly RPMs. The SV makes 65-70HP at around 9K RPM and a 600 I-4 makes 110HP at 13K+ RPM while a 12R (1200 I-4) makes 70HP at a hair under 5K, 110HP at about 7.5K and peaks at 165HP around 10K.

Torque and HP at low RPMs is nice to have on the street.

[taxonomy]

Originally Posted by ChR1s

Is there a pill for that?

No, you have to get it removed.

[taxonomy]

Originally Posted by ZX-12R

You can't truely have fun on a motorcycle unless you have at least 160 at the rear wheel. <SNIP>

Torque and HP at low RPMs is nice to have on the street.

My SV motor is just great. This may sound funny but I really liked my CB1 motor a lot too because it was so soft on the bottom. You could really roll the throttle open kinda sloppy and it didn't matter. You spent less of Code's dollar thinking about throttle. It would kick into "the pipe" as it came upright.

Simple.

But the SV is great too. It's new to me this riding season.

[taxonomy]

Originally Posted by Pigman

<SNIP>

got a set of Black anodized winshield bolts cheap.......plastic ones suck...
also a set of black leavers not bad quality at and for 25$ worth the money all day....long

One would imagine it would be hard to torque plastic bolts down enough to crack the windshild. Seems good to me.

So you bought AL windshield bolts from an online mail order company and them added them to your sig file?

A~

[ChR1s]

You've got your problems. I got my hash pipe.

[Jayspeed]

How about the weight loss and sound improvement?

[taxonomy]

Originally Posted by Jayspeed

How about the weight loss and sound improvement?

Wet weight = 425#
Rider in gear= 200#


Total 625#

What number of # will you have to loose to drop a meaningful percent?

By improved do you mean louder? OSHA will provide plenty of info about constant loud sounds inducing fatigue and causing errors.

[slowrider]

Sort of related to this, but either March or April BIKE magazine did a story on partial throttle dyno runs (20%, 40%, 60% openings). They did some comparisons between '08 and '06 ZX-14 and the newest GSX-R1000 vs the previous gen.

On paper, the '08 Kawasaki ZX-14 doesn't look like it was changed much but the partial throttle dyno runs look very different. The '08 ZX-14 supposedly has a lot more urgency at partial openings. While the GSX-R actually got a little softer (taming it).

I only got a pipe to distance my bike from the sewing machine syndrome. I'm trying to decide if it made my bike run too lean...snatchy throttle...I may have to go back to stock. That's all just my guess/feeling...

[Jayspeed]

Originally Posted by taxonomy

Wet weight = 425#
Rider in gear= 200#


Total 625#

What number of # will you have to loose to drop a meaningful percent?

By improved do you mean louder? OSHA will provide plenty of info about constant loud sounds inducing fatigue and causing errors.

Sorry I have no input on the power arguement with a slipon. All I'm saying is the other benefits a slipon will have. Less weight makes it easier to maneuver the bike. Louder and better sound than the stock cans. I admit part of my enjoyment in riding is hearing the engine(exhaust). Throttle response will increase especially if the slipon removes the catalytic converter which removes even more weight. Aftermarket looks better too. OSHA deals with work related issues so think about an example of what they would analyze like machinery or construction equipment. Sounds that you wouldn't want to hear continuously or even at all could cause fatigue because your so tired of hearing it. I'd never get tired of hearing my exhaust.

[taxonomy]

Originally Posted by Jayspeed

Sorry I have no input on the power arguement with a slipon. All I'm saying is the other benefits a slipon will have. Less weight makes it easier to maneuver the bike. Louder and better sound than the stock cans. I admit part of my enjoyment in riding is hearing the engine(exhaust). Throttle response will increase especially if the slipon removes the catalytic converter which removes even more weight. Aftermarket looks better too. OSHA deals with work related issues so think about an example of what they would analyze like machinery or construction equipment. Sounds that you wouldn't want to hear continuously or even at all could cause fatigue because your so tired of hearing it. I'd never get tired of hearing my exhaust.

You're going to knock off what? Maybe 15 pounds off a bike and rider combo that weighs, maybe, 650 pounds? It could not possibly matter. It also comes off the bike low down.

The throttle response argument is generally based on harmonics. That's going to depend on escape velocity of gas. The "stronger" signal is going to be either better or worse, depending on throttle position and rpm. Stock systems are highly tuned by very, very smart people that designed the whole engine in the first place. Modern EXUP style exhaust valves are meant to work as a system.

At some level loud is just loud. I have no idea why people think loud is good, it's just loud. When you ride your responding to input that competes for your attention. I would assume you'd want to minimize inputs that contained no relevant data, like exhaust noise. Even the tightest stock exhaust will tell you all you need to know.

A

[Jayspeed]

Originally Posted by taxonomy

You're going to knock off what? Maybe 15 pounds off a bike and rider combo that weighs, maybe, 650 pounds? It could not possibly matter. It also comes off the bike low down. A

Any weight reduction will help over all manuvering and also help your suspension.

Originally Posted by taxonomy

The throttle response argument is generally based on harmonics. That's going to depend on escape velocity of gas. The "stronger" signal is going to be either better or worse, depending on throttle position and rpm. Stock systems are highly tuned by very, very smart people that designed the whole engine in the first place. Modern EXUP style exhaust valves are meant to work as a system. A

Alls I know is after I installed my slipon, my front tire would leave the ground rolling on the throttle when it didn't before. Stock systems are designed for optimal function including the restrictions that must be included to follow environmental laws. I never removed any exhaust valves.

Originally Posted by taxonomy

At some level loud is just loud. I have no idea why people think loud is good, it's just loud. When you ride your responding to input that competes for your attention. I would assume you'd want to minimize inputs that contained no relevant data, like exhaust noise. Even the tightest stock exhaust will tell you all you need to know.
A

This depends on how you enjoy your riding and how many things you can concentrate on at once.

[seth505]

ok, so my aftermarket exhaust that is lighter and my marchesini forged wheels that are lighter are not going to make my bike perform better than a stock zx636?? (not all of us are 200lbs, some of us are 150 even) Also, I prefer to be able to rev my bike and have the car to the right of me that is merging into me and about to crush me HEAR that I am there...that is just me though.

I also think you would not enjoy my truck as it does not have stock exhaust either... And no it did not change my power at WOT only

[seth505]

Originally Posted by taxonomy

At some level loud is just loud. I have no idea why people think loud is good, it's just loud. When you ride your responding to input that competes for your attention. I would assume you'd want to minimize inputs that contained no relevant data, like exhaust noise. Even the tightest stock exhaust will tell you all you need to know.

A

One question, how do gp racers concentrate on being the best riders in the world? They have very loud bikes, do you ever ask yourself why their mechanics do not make them super silent exhausts, more like stock?

[ZX-12R]

Originally Posted by taxonomy

You're going to knock off what? Maybe 15 pounds off a bike and rider combo that weighs, maybe, 650 pounds? It could not possibly matter. It also comes off the bike low down.

I love how all of your conclusions usually sound something like "I don't understand the benefits therefore there are no benefits." There are lots of places on a bike where you can shed pounds. When you start combining them, it becomes pretty significant (especially rotating masses).

Originally Posted by taxonomy

The throttle response argument is generally based on harmonics. That's going to depend on escape velocity of gas. The "stronger" signal is going to be either better or worse, depending on throttle position and rpm. Stock systems are highly tuned by very, very smart people that designed the whole engine in the first place. Modern EXUP style exhaust valves are meant to work as a system.

Huh??? Throttle response is not even remotely based on any one property of the engine. You seem to be forgetting intake cams, exhaust cams, porting, jetting/fuel mapping, RPMs, compression, and the like before you even get to the exhaust system.

Stock exhausts are not designed to get maximum performance from the engine. They are designed to meet noise and emission requirements for the area they will be sold in (lean fuel mapping at certain RPMs too).

Originally Posted by taxonomy

At some level loud is just loud. I have no idea why people think loud is good, it's just loud. When you ride your responding to input that competes for your attention. I would assume you'd want to minimize inputs that contained no relevant data, like exhaust noise. Even the tightest stock exhaust will tell you all you need to know.

Here we go again with the "I don't understand the benefits therefore there are no benefits" mentality. Believe it or not but people ride for all sorts of different reasons and for some the loud scream of a race pipe on an I-4 or the deep "potato-potato" from a V-twin with mini pipes adds to their experience. By your reasoning no one should own an SV-650 because a Ninja 250 costs less, burns less fuel, and can still exceed the speed limit on any road in the USA.

[BCT748]

Originally Posted by taxonomy

You're going to knock off what? Maybe 15 pounds off a bike and rider combo that weighs, maybe, 650 pounds? It could not possibly matter. It also comes off the bike low down.

The throttle response argument is generally based on harmonics. That's going to depend on escape velocity of gas. The "stronger" signal is going to be either better or worse, depending on throttle position and rpm. Stock systems are highly tuned by very, very smart people that designed the whole engine in the first place. Modern EXUP style exhaust valves are meant to work as a system.

At some level loud is just loud. I have no idea why people think loud is good, it's just loud. When you ride your responding to input that competes for your attention. I would assume you'd want to minimize inputs that contained no relevant data, like exhaust noise. Even the tightest stock exhaust will tell you all you need to know.

A

What about bikes that have an under tail exhaust? All that weight would be dropped off the top end of the bike.

I guess you should send an e-mail to Ducati telling them not to bother putting Termi cans on their non-base model bikes. I guess them using them is just a waste of money and is only going to distract the rider with the louder sound. They should just use the heavy base model cans on all their higher end models, shit why not use it on the Desmosedicci too!!!

[taxonomy]

Originally Posted by BCT748

What about bikes that have an under tail exhaust? All that weight would be dropped off the top end of the bike.

I guess you should send an e-mail to Ducati telling them not to bother putting Termi cans on their non-base model bikes. I guess them using them is just a waste of money and is only going to distract the rider with the louder sound. They should just use the heavy base model cans on all their higher end models, shit why not use it on the Desmosedicci too!!!

What, an screw up the whole Ducati Lifestyle Marketing?! Next think we'll be stopping Vespa owners from drinking mochas. The benefit here is sales benefit. A pipe is a feature that people will pay for.

I just think at part throttle there's no really no benefit and there will be some drawbacks across large portions of the rev/throttle position matrix. 99% of us aren't using even 50% of the motor, so it doesn't matter. Like it or not it's just not that simple, pipe just doesn't equal more power everywhere all the time.

For people that are racing and for very fast people on tracks there may be marginal benefit. That's what I got from Kevin Cameron. There's no benefit at part throttle.

If you're bike isn't making it for you at WOT, by all means, get a pipe.

I have a Puch moped. Interestingly there's a whole lot of performance parts for it. To totally rebuild the engine with new block, head, intake, pipe, carb etc. is about $500. I'm going to see how I can tune it. Maybe double the HP from the 1.5 it's cranking out now. As it's run at WOT the pipe will matter across part of the rev range.

People are confusing all sorts of things here but the stronger signal is going to help part of the time and hurt part of the time. Fueling side solutions like rejetting and power commanders can clean up mixture but won't change the harmonics going on inside the pipe.

Most people I think get a pipe and they go out with the bike and nail it and the front end comes up or whatever and they feel good about it. But it's not the whole story, they didn't do that before the bike had the pipe, there's no base line. They're testing one aspect of performance. The bike sounds "meaner" or whatever. That kind of testing wouldn't make it into the worst peer review journal.

Paraphrase of my conversation with Mr. Cameron:

Me: So the best indicator that you could use the performace from an aftermarket exhaust is that you ride at WOT?
Cameron: Yes
Me: At part throttle there's no benefit?
Cameron: It depends on the escape velocity of the gasses, it could be better or worse but more or less they are tuned to produce at WOT. Under that it's a crap shoot.

This said, if you retain the EXUP style valves the potential drawbacks of adding a pipe could be ameliorated and the stronger signal could have some broad benefit across the whole throttle/rpm matrix, not just at WOT for part of the RPM range. In many cases on modern bikes a slip on may be a better solution that a full system for real world riding if a full system would eliminate exhaust valves.

To address your comments on Ducati, these systems were likely designed part in parcel with the engine development. So, smart people that knew the whole picture from the ground up were likely involved.

[Kurlon]

So, doing a little research on one Mr Cameron, I find he's a moto journalist with a tuning background based on older two strokes. (This is backed up by the EXUP valve comments, exhaust valves on 4 stroke bikes are typically installed just to meet noise tests, not for performance... That also matches his pipe theory, most two smoke 'race' systems were built for higher throttle openings, with the machine turning near peak power. It's not the only way to build a pipe though.)

Why is his opinion carrying more weight than others? You seemed to have fixated on it, ignoring any opinions as to why it might not be 100% dead on rather than having the fun technichal discussion this could be. We can't have a good debate if every responce is 'Nuh uh, Kevin said it was this.'

[taxonomy]

Kevin has been around for years. For some time I read a bunch of conbustion engineering stuff. He's also an engineer. Basically, air is elastic, or it has elastic properties. Stuff happens.

It turns out I am wrong. It all happens by Magic. I pipe is a magic box that makes magic happen at all RPMS and invisible faries pull the motorycle forward when they are not redeeming the baby teeth of children for golden coins.

[Kurlon]

Again, what makes one engineer's theory better than another's? Some of us are offering our opinion based on direct observation, measurement, and theory. I've been discussing motor theory with many engineers who are also guys that build crazy fast motors, and often times they have differing ideas yet they are all able to produce practical results... so which of them are wrong? If their ideas differ with Keith, does that make them or Keith wrong?

Unfortunately for you, thanks to my hand injury I've got nothing but time to pursue this, so half assed childish rebuffs won't detur me.

[Jayspeed]

Originally Posted by taxonomy

Kevin has been around for years. For some time I read a bunch of conbustion engineering stuff. He's also an engineer. Basically, air is elastic, or it has elastic properties. Stuff happens.

It turns out I am wrong. It all happens by Magic. I pipe is a magic box that makes magic happen at all RPMS and invisible faries pull the motorycle forward when they are not redeeming the baby teeth of children for golden coins.

Boy, the aftermarket exhaust lies have been fucking people over for years now and you have finally figured it out for the world.
Heck...lets start a sueing campaign. We can all meet at Starbucks and talk about it.

[SSearchVT]

Exhaust systems do alter the power delivery when installed correctly - even at part throttle. The entire system needs to be considered from where the air enters the airbox to it leaving the end of the silencer. Before this, a decision needs to be made about the way the bike will be ridden.

For example - by changing the expansion chamber, jetting , and adding a heavier flywheel - a 2 stroke 125 MX machine becomes much easier to ride in the woods (low RPM, partial throttle). With a different chamber, jets, and lightened flywheel - the same machine is good for MX (high RPM, WOT).

In a 4 stroke inline 4 - by altering the length and diameter the individual headers run before they hit a collector will affect the partial throttle performance. Smaller diameter tubes will keep the exhaust velocity higher at part throttle situations, and the shorter the distance to the collector affects the scavenging effect. The harmonics of the exhaust pulses needs to be accounted for as well to limit backfeeding.

Do you think the factory race teams use the same exhuast system for every race at every track? From the outside they may look really similar, but they are custom built for those race conditions based on what the data loggers have reported from testing sessions in similar situations.

Motorcycle manufacturers do not design the bikes for peak performance. They design them to meet the requirements of the government where the bikes will be sold, meet a certain price point for manufacture, deliver a level of reliability, and lastly deliver an acceptable level of performance for the target buyer.

[taxonomy]

Originally Posted by Kurlon

Again, what makes one engineer's theory better than another's? Some of us are offering our opinion based on direct observation, measurement, and theory. I've been discussing motor theory with many engineers who are also guys that build crazy fast motors, and often times they have differing ideas yet they are all able to produce practical results... so which of them are wrong? If their ideas differ with Keith, does that make them or Keith wrong?

Unfortunately for you, thanks to my hand injury I've got nothing but time to pursue this, so half assed childish rebuffs won't detur me.

The exhaust valve closes. The air that left is still moving forward. A low pressure area forms behind this "chunk" of moving gas.

From the valve opening and closing we would wind up with positive and negative waves of pressure in the pipe. Look up four stroke exhaust tuning.

These pressure waves will have good and bad effect depending on when they arrive at the valve. The timing of this would be, in large part, due to the escape velocity of the gas. The escape velocity of the gas would depend on the pressure of the gas that is escaping the cylinder. This would be determined to a great degree by the amount of gas ingested by the motor, throttle position.

You would want that negative pressure wave to arrive at the exhaust valve just when the valve opens and to maintain itself through valve overlap.

You should be able to see that there's a lot of things effecting that pressure wave. They are not very commonly discussed but they are there.

Also, there is a possible bad affect too. The positive pressure wave could arrive at the exhaust valve when it's open.

There is so much going on there that's it just about impossible to arrange things to work all the time.

EXUP type valves are meant to deal with this.

The same harmonic system exists on the intake valve side. Honda attempted to get around this first with telescoping intakes on the NSR, I think and I think Yamaha has a simpler variable intake length scheme on the R bikes.

All I am saying is that reduced restriction is going to amplify these effects, good and bad.

I am also saying that at part throttle you're not making max torque. If your dyno chart says 50 ft lbs of torque at 5000 rpm it's only making that at WOT.

Why? The engine is ingesting and compressing less gas than it would be at WOT reducing BMEP (brake mean effective pressure) and thus, torque.

If you are not using the full amount of torque (riding at WOT) adding more does not do any good.

Throttle response may be increased or decreased depending on your throttle position, and RPM and how the pipe interacts just there.

If there was, theoretically, an increase in throttle response we would have to demand it to make use of it.

In a situation where we roll on the throttle I doubt that anyone here is doing it quickly enough so that we are going to ask for more response than the stock bike is capable of delivering when the bike is leaned over exiting a corner considering the type of hardware that people are using on this list.

[taxonomy]

Originally Posted by ZX-12R

I love how all of your conclusions usually sound something like "I don't understand the benefits therefore there are no benefits." There are lots of places on a bike where you can shed pounds. When you start combining them, it becomes pretty significant (especially rotating masses).

I am limiting the scope of this conversation to pipes alone.

Originally Posted by ZX-12R

Huh??? Throttle response is not even remotely based on any one property of the engine. You seem to be forgetting intake cams, exhaust cams, porting, jetting/fuel mapping, RPMs, compression, and the like before you even get to the exhaust system.

True, again the scope of this conversation is pipe alone. We're just taking about the pipes here. It's hard enough talking about just that.

Originally Posted by ZX-12R

Stock exhausts are not designed to get maximum performance from the engine. They are designed to meet noise and emission requirements for the area they will be sold in (lean fuel mapping at certain RPMs too).

Fuel mapping is another thing altogether. They are related, but then we might as well start talking about ignition and/or valve timing too. I never brought them into the conversation. What I am talking about is the how I understand that a pipe works on a bike and its practical application to street sport riding.

Originally Posted by ZX-12R

Here we go again with the "I don't understand the benefits therefore there are no benefits" mentality. Believe it or not but people ride for all sorts of different reasons and for some the loud scream of a race pipe on an I-4 or the deep "potato-potato" from a V-twin with mini pipes adds to their experience. By your reasoning no one should own an SV-650 because a Ninja 250 costs less, burns less fuel, and can still exceed the speed limit on any road in the USA.

Wow, that's awesome, I wish I had thought of it.

But seriously, I am mostly talking about what I think of as conventional sport riding as I have seen it done. This meaning 100-200% of the posted speed limit on two lane numbered state routes. I am also not talking about high straightaway terminal velocities here.

I think there's some convention to this, it's how I have seen people ride. If you want to go 110 on public roads that's something else entirely. But in fast out of the pocket riding on curvy roads I don't think people are using peak torque and I don't think they are demanding the maximum rate of change in RPM (throttle response). Given that this is really what a pipe effects I still think that, aside from weight, the best indication you could use a pipe is riding at WOT, something you'd likely do on a Ninja 250 on public roads and still be kind of responsible.