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I always love when people don't understand the responsibility of owning a computer, nor do they understand that the words which they post, are untrue in many cases, that they actually hurt a company's new bike.

For those in the ROW (Rest of World), I am sorry for you, as this is the muffler set you will get. For you US Wankers, you really need to check your facts, the US version will come with the standard under engine type exhaust.

You think it is even responsible to start a horse shit post like this especially when you have no idea what you are talking about...

Thor
Here is the funny thing...nowhere in the original post did he referring to the pictured bike being the US version...

To follow your outstanding intro...I always love when people don't understand the responsibility of owning a computer, nor do they understand the words which they are commenting on, causing irrelevant statements in many cases, that they actually hurt a forum's value and etiquette...
 

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Quite the fickle bunch...

For those questioning the exhaust location, take a second and think about it logically. Ducati superbikes are first and foremost PERFORMANCE machines. And as such they are built to maximize performance. The underseat exhaust, though boner inspiring, raises the center of gravity, increases rotational inertia thus decreasing flickability. So a side mount exhaust is better, and an under-body exhaust is best. However, back to the emissions problem, they probably can't package the requisite emissions compliant exhaust between the wheels so they put it in the next best place - on the side.

Times are changing and Ducati as well as every other manufacturer must change with it. Change can be painful. The 916-996 series Ducatis were the most beautiful bikes around. Then came the 999. WTF said everyone. But guess what? Those bikes were faster around the track. Then after a few years Ducati returned to its sexed up form with the 1x98 series.

You don't like the 959? Don't buy it. Either find yourself a 916, 1x98, or wait a generation or two when Ducati will redesign their Superbike again.

I personally prefer the 1x98 series to the Panigales, but that doesn't mean I suddenly hate Ducati and go running to the next attractive marquee, nor does it take away from Ducati's history of success.

Sorry, /end rant. Just bothers me to see all these "groupies" profess their love for a marquee one minute, then the next bash it as if it's ruining their life.
 

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I kinda wonder why would motogp put it under the tail if that's not the best place...

Not to mention I find mine extremely easy to flick
 

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I kinda wonder why would motogp put it under the tail if that's not the best place...
The 2016 YAMAHA M1 at the Valencia/Jerez tests
placed the fuel tank back there.

But typically it does have disadvantages having weight so far back, it pays to lighten up the under tail exhaust. Flickability with a higher CG is misguided. The side exhaust on the bike is likely a packaging/manufacturing solution rather than to make the bike more flickable.

Lowering the CG or having the exhaust underneath helps with stability, braking, less wheelies, and the underbody exhaust is also the new styling trend... Sucks for engine performance... (ironic perhaps?)
 

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Discussion Starter #27
I always love when people don't understand the responsibility of owning a computer, nor do they understand that the words which they post, are untrue in many cases, that they actually hurt a company's new bike.

For those in the ROW (Rest of World), I am sorry for you, as this is the muffler set you will get. For you US Wankers, you really need to check your facts, the US version will come with the standard under engine type exhaust.

You think it is even responsible to start a horse shit post like this especially when you have no idea what you are talking about...

Thor
Hey buddy, if you like the fugly exhaust, just admit it! And I DON'T GIVE A FLYING FUCK who gets the FUGLY exhaust or not, It's still YOU-GEE-EL-WHY...

P.S. PLEASE don't procreate! Just do this :jerkoff:
 

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Higher CG increases flick-ability actually... Didn't bother reading the rest.
That's what I always thought too, which makes me wonder why more bikes don't/didn't have that. Aside from some of the Ducs, the R1 had under tail exhaust for a couple of generations, the CBR600 still does, CBR1000 had it for a generation or two, Kawasaki had it on their older 636 and a ZX10 generation, and the MV Agusta F4. That's about it as far as sport bikes.

I wonder what manufacturers' reasons are for choosing side exhausts vs under tail vs under belly.
 

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I always love when people don't understand the responsibility of owning a computer, nor do they understand that the words which they post, are untrue in many cases, that they actually hurt a company's new bike.

For those in the ROW (Rest of World), I am sorry for you, as this is the muffler set you will get. For you US Wankers, you really need to check your facts, the US version will come with the standard under engine type exhaust.

You think it is even responsible to start a horse shit post like this especially when you have no idea what you are talking about...

Thor
 

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Higher CG increases flick-ability actually... Didn't bother reading the rest.

Admittedly it's been awhile since I've done FBDs but help me out here. Correct me if I'm wrong; this is how I understand it.

Let's talk about a chicane with quick left-right-left transition as an example. For simplicity we'll ignore gyroscopic effects of the wheels, crankcase, etc as they'd be the same regardless of the CG/exhaust location. From upright, all forces push down in line through the CG to the contact patch and the bike is stable. You exert a side force (through counter steering but we won't go into that) to initiate the first turn and the bike leans. Now the combined CG -- you + bike -- produce a torque on the bike due to your weight/gravity acting away from the pivot point or contact patch. If you have a higher CG, the moment arm is longer. Which means there's more torque and more inertia or resistance to rotate the other direction thus requiring higher forces than if you had a lower CG. The lower CG would have a shorter moment arm to the contact patch providing less resistance and making the change of direction easier.

Now that's just basic physics torque = force x distance.

For undergraduate level discussion we can use moment of inertia (I), resistance to rotation, where I=mr^2.

M=mass
R^2=radius between that mass and the point of rotation, squared

Normally it would include the integral of all the mass along the body but again for simplification you can use CG and treat the bike as a pendulum.

Now since the radius is squared, clearly the further the mass is from the point of rotation, the larger the moment of inertia and thus the more torque required to cause said mass to rotate. In the case of our bike, a higher CG would be harder to change direction quickly.

Where did I go wrong here?
 

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Ahhh...a fellow engineer! Nerd talk! Got me all excited now! :D

I'm going to split this into 2 big categories:

1) Realistic point of view:...it doesn't matter. Yamaha bikes in GP with a side exhaust have won many a races. So has HRC with their undertail exhaust + side exhaust. In Moto 3, the Hondas with the undertail exhaust have also won plenty, as did the KTM's and other bikes that had lower mounted side exhausts. The difference is so minimal, that I'm willing to bet that "flickability" is a VERY small factor for manufacturers in deciding where/how to mount the exhausts.

2) Scientific point of view...you're not wrong IMO, in the example you gave. However that's only part of it. In a case of a chicane, especially a double or triple chicane (think the section at COTA starting at turn 3 for example), I would say your reasoning is correct. However when I think of "flickable", I don't think of how easy it is to transition from one side to the other, but also how easy it is to turn in, for just a single turn, which occurs much more on tracks than chicanes do. Most tracks only have 1-2 chicanes, and many more individual turns. In that case, using your pendulum analogy, wouldn't you think that by having that extra mass at the top, resulting in a higher moment, make the bike "drop" into the turn faster?? I think it would....sure once it's there, it'll be harder to get back up, but that will only hurt you in chicanes. Do you want to build a bike that's good for only 20-30% of the track, or one that's good for 70-80%? Everything is a compromise! There is no such thing as PERFECT setup. You sacrifice one thing to hopefully improve something that benefits you more. That's just what I think of when I refer to "flickability".

On the other hand, there's the going through a corner part, where you have to account for the centripetal force, which is what's allowing the bike to lean over so much without falling over. Having a higher CG, means the CG will be farther away from the tire contact patch, therefore the gravity vector would be farther away, resulting in a higher moment. This would be much easier shown with a FBD :eek:. The forces have to be balanced, or else you fall, or you go the other way (high-side). If your gravity vector is farther away, that means the centripetal vertical component force has to be higher in order to balance it. That would require a higher horizontal component as well (assuming fixed lean angle). That means you're speed has to be higher, or the radius of the turn smaller, and now you're exerting more force in the horizontal direction which is being balanced by the friction force between the tire and track. Go too much and you go over the edge, exceeding that force and you crash. So in that case, a higher CG means more risk mid-turn or throughout a turn. It's hard to think of, and I may have just confused the shit out of myself as well, but I'm sticking to it for now until proven otherwise :D...when in doubt, I like to think of extreme cases. In this one, think riding a bicycle, where the CG is much higher up because most of the total weight is from the rider, up top. Ever drag a knee on a bicycle in a turn? Probably not. If you lean a bit too much, the centripetal force can't balance gravity and you go down. You'd have to go much faster to lean it more, at which point those skinny tires that are not meant for that, are probably going to give out and you'll slide.

So in the end, going back to the compromise thing. Just considering geometry and physics, I believe there are pros and cons for having a lower or higher CG, so it's all about what you want to give up and what you want to gain. I still think the difference is very small, and the position of the exhaust makes jack shit of difference as far as performance goes. Now as for personal preference, I like undertail and under belly exhaust, but that's because I simply like symmetry, makes it easier to take the wheel off if the bike has a SSSA, and has much lower chances of getting damaged in a crash :)
 
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Random,

Your reasoning is logical, but it doesn't work like that.

Everything being the same (pmi for example) with only the CG moved upwards, think about it this way... and keep in mind that the motorcycle is generally turning in a circular path when it's leaned over.

1. In a straight line, it takes less effort to lean the bike over if you have weight up higher.
2. Once in a turn and leaned over, a higher CG mans that the CENTRIFUGAL FORCE acts on a longer lever arm to help you flick the bike back the other way.

Aside from that, if you raise the front and rear of your bike the same amount, let's say 5mm, you will notice it's much livelier transitioning left and right. It will also pitch forward and aft easier, so that's the drawback which needs to be balanced.
 

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See also the low CG bike developed by engineers thinking the same as you... the 1984 NSR500.

It secretly had the fuel tank underneath creating the bottom V of the bike, the reason being a low CG in order to make the new machine "more flickable". It failed as it was very slow to turn.
 

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Oops...I suppose I used the wrong term. Centripetal force is what keeps it going in a circular motion, and centrifugal is what the bike/rider are feeling (being pushed away from the turn). Good points, especially #2...good way to think about it.

Personally, I've always felt a difference when going out on track with a full tank vs almost empty tank. With a full tank I always felt like it turned quicker....but it's once you're at lean that the negative things happen, and the risk of crashing increases (the stuff I mentioned in the 2nd half of my post).
 

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Oops...I suppose I used the wrong term. Centripetal force is what keeps it going in a circular motion, and centrifugal is what the bike/rider are feeling (being pushed away from the turn). Good points, especially #2...good way to think about it.

Personally, I've always felt a difference when going out on track with a full tank vs almost empty tank. With a full tank I always felt like it turned quicker....but it's once you're at lean that the negative things happen, and the risk of crashing increases (the stuff I mentioned in the 2nd half of my post).
fuel light on + still out on track = A) good wheelies or B) "$hit...i'm that guy who ran 'er dry.."

i.....well..i've been both. .:p
 

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fuel light on + still out on track = A) good wheelies or B) "$hit...i'm that guy who ran 'er dry.."

i.....well..i've been both. .:p
Haha yep!...thankfully, I have yet to run out of gas...EVER, bike or car, track or street. Hopefully I didn't just jinx myself now :eek:
 

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Why is that they do not use a single sided swinarm since the 848? I think seeing the back wheel makes the bike, love my 848 even more now..

I didn't buy a new 959 for this reason. The loss of the single sided swing arm was a deal killer for me. Even though I KNOW the 959 is a kick Butt bike! Saving my pennies for a new 1299S.......... Have to slum it on my old 1098S for now :)
 
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