I have loud pipes on my 907 now and I found the original factory pipes on Ebay and bought them cheap.Can I just put them on without any jetting or changes.Thanks...

so why do guys race with 50 or 60mm headers and open exhausts ? Motorcycle races would be way less noisy if they would use the original exhausts instead
I guess the correct way would be to say that aftermarket cans can provide more horsepower.
I`ve seen tests of aftermarket exhausts compared to an original exhaust on a stock bike and actually numerous aftermarket cans were worse than the original. They made more noise than the original but often produced less power.
Things change (depending on the aftermarket exhaust system used) if the engine is modified and/or setup correctly to the exhaust (ie so it doesn`t run lean). The additional power will come if the combinations of all modifications is correct. This takes a lot of experience and knowledge. that I unluckily don`t have

G.

Guys, go slow.
Although Antti likes to be provocative sometimes i think we can agree that it`s often a matter of misunderstanding and of guys discussing who`s mothertongue is not english which includes me, too.
I would agree with you both. An aftermarket exhaust alone (with no other tweak) will change very little to nothing. The engine may aspirate better but it will not produce more horsepower. Actually it will run lean (still speaking of an original untouched bike). If you then reprogram the Eeprom to match the exhaust you will get more fuel in the compression chamber. That is when you will get more power.
If you two disagree to this little summary, continue to bash your heads - I`m outta here

Guys guys guys,tsk,tsk,tsk. Changing the exhaust on any fuel injected engine without remapping the eprom will
1 make more noise
2 make the engine produce less power
Changing the exhaust and remapping the eprom alone will
1 make more noise
2 make the engine produce less power
There is nothing to discuss or anything worth arguing about. It is a simple proven fact. Period
Now if you change the exhaust with a corresponding change to the intake airflow and the proper remapping of the eprom it is possible to wring out a little bit more power. a few ponies more
Adding more fuel will just make your engine run richer.
Internal combustion engines run on air.
to get more power you have to get more air into the engine or compress the air more. That's it there is no other way.( well almost no other way,there is always accelerants like oxygen)
Fuel is simple the agent used to heat the air. Fuel will only heat the air properly at 14.7 to one That is 14.7 units of air to one unit of gasoline by mass.
Generally it will take more than remapping and Exhaust and intake mods to get a real increase in power. Cam timing needs to be considered to get real improvements and most of those kind of improvements require higher rpm, but raising compression is still the best way to go. ADD CUBES OR ADD PRESSURE. or

Macwig, you have just as good a chance as not to find the stock exhaust will make your 907 run better,the only way to find out is put it on, anything else is bullshit If you put it on and it runs worse,then the controller has been remapped and you will have to find a way to deal with it. Throw in if your airbox has been modified and it could get complicated
Let us know what and how you make out, Even Antti will be interested to know

Ahhhrrr come on guys don't back down just now I was really looking forward to a Duel at Dawn with your Eprom chips in one hand and Exhausts in the other.

United Nations here we come.

I read this topic queit and quick.
this must be the first time that the guys who react make more noise than theyre exhausts
But still: no power or torq
if you want to change the cans for a more open type you HAVE to consider the whole sytem otherwise you produce just more music. In case of any Paso I don't talk of noise

ducbertus