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Need Advice regarding exhaust

Old 08-01-2013, 04:37 AM
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Need Advice regarding exhaust

Hello Guys, I need your opinion on what I am about to do with my bike

I ride a 1999-2000 Honda VTR Firestorm 1000f, I got it stock and one of the first things we did was to open up the exhaust by changing the tip, Basically to let it breath and make a bit of noise. I have been using it for some time already but I did notice that the top end was not so powerful anymore (maybe just my imagination) but some friends say that the exhaust is too big. What do you think?

Anyway, I am planning to remove the Dual exhaust replacing it with a single carbon yoshimura exhaust from another liter bike (gsxr1000). Some friends say that it will run better some say it won’t have much breathing space.

Seeking for your personal expert advice

Thanks!
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Old 08-01-2013, 06:30 AM
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I love my Devil exhaust. It sounds awesome, not too loud, and runs fine. It was installed by an owner past, so I am not sure if he jetted the carb or not at the same time.
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Old 08-01-2013, 06:55 AM
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There are different schools of thought, but I would suggest go to the following thread and you will find allot of good info to work with and make your call on what to do:
https://www.superhawkforum.com/forum...-setups-28999/
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Old 08-01-2013, 06:58 AM
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Originally Posted by patootoot! View Post
Hello Guys, I need your opinion on what I am about to do with my bike

I ride a 1999-2000 Honda VTR Firestorm 1000f, I got it stock and one of the first things we did was to open up the exhaust by changing the tip, Basically to let it breath and make a bit of noise. I have been using it for some time already but I did notice that the top end was not so powerful anymore (maybe just my imagination) but some friends say that the exhaust is too big. What do you think?

Anyway, I am planning to remove the Dual exhaust replacing it with a single carbon yoshimura exhaust from another liter bike (gsxr1000). Some friends say that it will run better some say it won’t have much breathing space.

Seeking for your personal expert advice

Thanks!

Usually if you go to open on the exhaust you end up with lower top end power due to decreased back pressure, same reason stunters, and I4 guys cut their pipes in half and rerivet them, gives more on the low end while taking away from the top.

It is possible to go to a single exhaust but its not easy and involves a lot more than just capping the exhaust and running 1 slip on. To get the bike to perform any where close to decent it will take a lot to trial and error tuning and good knowledge of exhaust flow and these carborators.

These bikes have poor exhaust flow from the factory, not the worst but not the best either, IMHO it is best to stick with dual exhaust and find a pair of slip ons to satisfy your craving for better sound. Proper back pressure is needed for any engine to run correctly, Hawks especially.


And remember this is just my $.02
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Old 08-01-2013, 04:24 PM
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Usually if you go to open on the exhaust you end up with lower top end power due to decreased back pressure
The same with longer cans. Short cans are the opposite and give you more top but sacrificing bottom. I'm not a fan of 2 into 1's The two exhausts was one of the things that attracted me to these bikes. I like the symmetrical look.

(:-})
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Old 08-01-2013, 04:27 PM
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backpressure doesn't generate power, exhaust gas speed does, there's tons of articles out there...but basically some Honda engineer spent a long time developing the stock exhaust shape, so unless you fancy yourself a gas flow specialist it may not be worth it to go to a 2 into 1 setup.

I did, and it was massively annoying getting the thing to run right...I only did it because one side of my exhaust got rusted and ruined (unsure how, it was like that when I got it).
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Old 08-01-2013, 04:45 PM
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Indeed it's a lot more complicated than just pressure but it's the velocity of the flow and the control of scavenging from the pulses as things change from a positive to negative pressure. The exhausts are a highly tuned length and when you start changing things you getting into an unknown territory and it could boil down to trial and error along with jetting to suit. It's a bit like porting heads, it's not always beneficial to open things up, yes you get more but it slows the velocity. Gas flow and fluid dynamics I think are closely related and highly specialist tools and knowledge are required. A very interesting area to read about but a bit of a Black art.

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Old 08-01-2013, 07:29 PM
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I agree, everything is tuned from the airbox to the tip of the exhaust, together. Pretty damn well! Honda knows many will add slip-ons and I believe factor this in re main jets. Two large pistons = large exhaust pulses. Thats why there are two huge cans on these bikes, so package can be tuned properly.

Last edited by jerryh; 08-01-2013 at 07:32 PM.
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Old 08-01-2013, 10:37 PM
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I have 2 vtrs, one 2 into 1 devil carbon, one two brothers dual slip ons. I like everything about the 2 cans better. Throttle response, sound, etc. I think its way easier to tune duals since I have spent alot of time tuning both.

The 2bros are actually high mounts that I converted to low mount to accomodate the givi rack. Doest like as trick but funtions way better.
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Old 08-02-2013, 05:14 AM
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Originally Posted by jerryh View Post
That's why there are two huge cans on these bikes, so package can be tuned properly.
Large cans = quiet exhaust note, to meet regulation. Size is only needed to muffle dB's.
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