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clean fight
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1,555 Posts
Discussion Starter #1
im hoping to put an under-engine style exhaust on my cbr. how different are mufflers from different bikes. cause theres some out there that i like their cans.
does a cbr 1000 can not work well on a 600?
shour it be another 600? does it need to have come off a 4cylinder bike?
will the shorter pipe length screw me ? itll be the same length as now running straight pipe.
it ends under my right rearset but i think i lost a bunch of power when i took the muffler off.
will an exhaust can on that same length shorter pipe bring back some of that guts?
thanks yall
 

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Ridin' Dirty
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6,773 Posts
I'm not sure i understand the question......



What bike is it?


In almost all cases, exhaust systems from other bikes will not just bolt on. With some fabrication, lots of things can be made to fit. Are you concerned with just mufflers, or headers too?

My understanding is that the most common effect exhaust changes will have on performance is a change in backpressure. If the bike is carbed, you can rejet accordingly, if it's FI, still need to adjust the fuel/air mix. PC is the most common thing i'm aware of, but i have almost no FI experience.
 

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clean fight
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1,555 Posts
Discussion Starter #3
I'm not sure i understand the question......



What bike is it?

its a 99 cbr600 f4-
and the question is pretty much:
how much will is screw my bike up to put an under-engine (shorter) or an under-tail(longer)
exhaust on? probly keeping the header same. using a can off another make/model/cc?
whats different between exhaust on a fuel injected bike than a carbed bike? like a new 1000rr can onto a 600 f4?
 

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Ridin' Dirty
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6,773 Posts
its a 99 cbr600 f4-
and the question is pretty much:
how much will is screw my bike up to put an under-engine (shorter) or an under-tail(longer)
exhaust on? probly keeping the header same. using a can off another make/model/cc?
whats different between exhaust on a fuel injected bike than a carbed bike? like a new 1000rr can onto a 600 f4?
Is that the carbed F4 or the F4i?

"How much will it screw it up?" is the wrong question to be asking. How do i do it correctly is the right question. If you plan on just bolting shit on and hoping your bike still runs, then you need to rethink touching your bike with tools. :D

As long as the exhaust changes are done correctly, ie, no crazy turbulence from exhaust diameter changes or bizarre routing, then as far as i know, the biggest issue will be the changes in back-pressure, aka, the resistance of the exhaust system. This will affect the flow characteristics of the mixture through your engine. You will then need to retune your fuel/air mix. On a carbed bike, that means rejetting, on an FI bike that means PCIII or the like. I have no idea if you can tune OEM FI systems without a PCIII or similar system.

There is no difference between the exhaust systems on a carbed bike or FI bike, just a completely different process for tuning.
 

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E=MC Vagina
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6,908 Posts
ck is right. you can do anything you want with-in reason and as long as its just an exhaust change you may not need to tune it at all. if you throw a high flow air filter at it as well then you will definaltely have to tune....either way its not that hard to do. carbed bikes are a little more time consuming but still fairly easy.
 

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Ridin' Dirty
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6,773 Posts
ck is right..
lol, who?





you can do anything you want with-in reason and as long as its just an exhaust change you may not need to tune it at all. if you throw a high flow air filter at it as well then you will definaltely have to tune....either way its not that hard to do. carbed bikes are a little more time consuming but still fairly easy.

Mustang is exactly right, but DONT assume you can get away without tuning the mixture. esp if you're considering going really short with the exhaust or really long, like an undertail. Those changes are significant enough to really affect backpressure.
 

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Trackday junkie
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139 Posts
Make/model specific that may or may not be generic.
With my last race bike I fitted an M4 full race system to it as well as a bunch of other changes. Then she spent a few hours on the dyno jetting her to suit.
It was getting fairly late and "someone" asked--Hey how will it run with the scorpion muffler --or with this (yoshi) muffler on it.
Ya know the variation was less than half a HP--so basicly nothing.
Probably just reiterating what the guys above said.
 

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clean fight
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1,555 Posts
Discussion Starter #9
thats good to hear actual 1st hand exp.
those yosh and scorpion mufflers are designed for your sepcific bike tho right? like a honda 600 inline 4 would be different than a honda v four or a yamaha 600?
 

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Trackday junkie
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139 Posts
thats good to hear actual 1st hand exp.
those yosh and scorpion mufflers are designed for your sepcific bike tho right? like a honda 600 inline 4 would be different than a honda v four or a yamaha 600?
The scorpion was off the origonbal zorst when the bike was a few HP down. The Yosh was off of a SV thou (I think)
 

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Ridin' Dirty
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6,773 Posts
thats good to hear actual 1st hand exp.
those yosh and scorpion mufflers are designed for your sepcific bike tho right? like a honda 600 inline 4 would be different than a honda v four or a yamaha 600?
If you're considering something, run the specific situation by us, you seem really hung up on the engine configuration.


I've seen guys on here run dirtbike silencers on I4s. Like xjxjxj said, once the bike is re jetted (carbs), or the FI is adjusted, the performance difference is probably negligible. I've always worked on dirtbikes, so i just jetted by the "ride and feel" method. But if you can access a dyno like xjxjxj did, it will make you life worlds easier and it will be quicker and more accurate.


Are you trying to squeeze a drop of extra hp, or do you just want to redesign your exhaust for street riding and dont want to lose a ton of power?
 

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clean fight
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1,555 Posts
Discussion Starter #12
yeaj i just dont want to screw my bike up. im not racing or anything. its a fighter style consideration. ive got a 2 bros on there that works and sounds great. but im putting a sssa on and want to move te big can so you can see the wheel. thats really it. just trying to get the exhaust out of the way of the wheel visually.
 

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Ridin' Dirty
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6,773 Posts
ok then, short answer is use whatever you want, as long as it's not a crazy inlet diameter. Dont change tubing diameter along the length of the exhaust, and dont do an real crazy routing, and you'll be fine.

If you're not good with jetting, we can help you.
 

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Ridin' Dirty
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6,773 Posts
awesome.
imnot good w jetting!
its basically moving the needle forewrd or back to let in less or more fuel to the mix right? air stays the same unless i change filter/intake?

Intake and exhaust both affect the airflow.

The carb has different circuits that control fuel and different throttle settings. The needle and the main jet only control from like 50%-100% throttle settings. The pilot system controls low throttle settings, etc...depends on the carb, some have a shitload of jets.

Dont get overwhelmed though, it's easy, just get your exhaust set up, do some reading on carb tuning, and let us know, we're here to help.
 

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God Of Wires
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237 Posts
sounds like y'all got this under control. Just wanted to add that a muffler is pretty much just a muffler. Its just a hollow metal object with baffles or a steel wool like packing etc. Like everyone said, put whatever you want on it, then tune your bike to match. Hell, I've run a Flowmaster muffler on a bike before just to see how it sounded...
 
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