Cutting Your Exhaust Pros & Cons??

[moosrdunk]

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Ive been thinking about cutting down my Twin Bros Exhaust for my 02 f4i basically for the looks factor and.. what are the (pros) if any vs the (cons) of doing something like this?.. will I have to then purchase a power commander etc to get the bike to run smoothly?

I found this link with the step by step instructions and the process looks pretty straight forward..

http://home.comcast.net/~nstama/shortyyoshi.html

 

[Green Machine]

I thought about this once as well, but it makes it so damn loud that you will end up getting pulled over and harassed more than its worth

 

[油井緋色]

Are you shortening it or cutting it off and running a horn shaped object? Cause the latter is extremely loud.

 

[moosrdunk]

Are you shortening it or cutting it off and running a horn shaped object? Cause the latter is extremely loud.

I would want to be cut the pipe to shorten it aswell as cutting the baffle down to match.. im assuuming this is what you were asking?.. by running a horn shaped object any image to show me what your referring to?

 

[bubbaloo]

I have Two Brothers slip ons and cut them down by about 6 inches. No noticeable increase in noise, Two Brothers have a nice deep tone anyways. They are more proportionate with the bike now, love them.

 

[Jimsun]

As long as its not carbs u dont have to worry about back pressure effect and rejetting issues

 

[meme]

The i in f4i stands for "injected"

 

[jord-rz]

It will change the tuned length of the exhaust. There will be a decrease in performance most likely, and probably no "pros" except the looks. Ive done it to a high mount hindle slip-on on a 03' zx6r, it looked much better and the performance loss was pretty much negligible.

 

[RockerGuy]

As long as its not carbs u dont have to worry about back pressure effect and rejetting issues

This is not entirely true.

OP, if there is no baffle it will get louder. I've cut 2 exhausts on my bikes, just looks better

 

[Low rider]

Only cons, no pros.

 

[Mina]

Only cons, no pros.

Looks better.

 

[RockerGuy]

Just remember to wear long sleeves & gloves when handling the packing. I wear a dust mask too

 

[MarcosSantiago]

Looks better.

Not sure about that, but I guess it is in the eyes of the beholder.

Everytime you mess with the exhaust, there are changes to the performance. Most of the time, negative changes.

Myself, I would save my money and buy the new pipe that I really want. Is there any shortie pipe available for your bike?

 

[Mina]

I personally have the shorty Akra on my 750 and a long Akra on my 600. I don't think they make a shorty for the F4i.

 

[RockerGuy]

Not sure about that, but I guess it is in the eyes of the beholder.

Everytime you mess with the exhaust, there are changes to the performance. Most of the time, negative changes.

Myself, I would save my money and buy the new pipe that I really want. Is there any shortie pipe available for your bike?

What do you mean negative ? As long as its tuned, should be ok

 

[油井緋色]

I would want to be cut the pipe to shorten it aswell as cutting the baffle down to match.. im assuuming this is what you were asking?.. by running a horn shaped object any image to show me what your referring to?

http://www.motorcycle-superstore.com/15324/i/jardine-gp1-dual-slip-on-exhaust

Like these. I have a friend that has something similar, no baffle, horn shaped (sound amplification). We can't even talk to each other on red lights lol

Yes it looks better but it's about as heatscore-ish as typical undertail fender eliminators.

 

[moosrdunk]

http://www.motorcycle-superstore.com/15324/i/jardine-gp1-dual-slip-on-exhaust

Like these. I have a friend that has something similar, no baffle, horn shaped (sound amplification). We can't even talk to each other on red lights lol

Yes it looks better but it's about as heatscore-ish as typical undertail fender eliminators.

oh ok well this wasn't something I was even thinking about but would be open to something like this aswell. but much smaller

 

[Brian P]

What do you mean negative ? As long as its tuned, should be ok

Not quite. Changing the tuned length and changing the amount of damping at the end will change the way the pressure waves bounce around in there. If that ends up sending a "bad" reflection back to the engine, it will run poorly in whatever RPM range it affects and no amount of fiddling with the fuel injection will solve it. You can make it run "less badly" but never "good", if the engine is being made to swallow a reflected positive pressure pulse of exhaust at the wrong time.

Exhaust systems for street bikes are designed and tuned to function correctly when they have a muffler at the end. Usually, taking it off will make the engine lose power. Shortening it isn't quite as bad as completely removing it, but it's heading in that direction.

 

[Brian P]

Keep in mind also, that more noise = more attention from the police. Smaller muffler is heading in the direction of more noise. To be quiet without being restrictive, a muffler needs to have more internal volume.

 

[RockerGuy]

Not quite. Changing the tuned length and changing the amount of damping at the end will change the way the pressure waves bounce around in there. If that ends up sending a "bad" reflection back to the engine, it will run poorly in whatever RPM range it affects and no amount of fiddling with the fuel injection will solve it. You can make it run "less badly" but never "good", if the engine is being made to swallow a reflected positive pressure pulse of exhaust at the wrong time.

Exhaust systems for street bikes are designed and tuned to function correctly when they have a muffler at the end. Usually, taking it off will make the engine lose power. Shortening it isn't quite as bad as completely removing it, but it's heading in that direction.

Input??

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