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Discussion Starter · #1 ·
A freind of mine who happens to be a former honda service dept. employee, suggested that if I put on a slip on exhaust that took the flapper out, that I would lose mid-range power but gains at the top of the rev range. I'm not too sure I buy that thoery since the "flapper" is non-existent in the racing arena. Your thoughts on this? Anyone have any real life dyno comparisons to bust this myth?
 

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Sounds about right, doesn't the flapper do the same job as the EXUP on the Yamaha? I was gutted when I fitted a full system to my '00 R1, it did make more grunt in the higher rev range but made low speed riding through traffic a nightmare. It wouldn't carburate properly if you gave it a fistful until it got above certain revs.

I assume the fuel injected bikes can handle the loss of the butterfly better, although if I do buy a blade I think I'd rather leave it in place and get a slip-on can instead.

(I sold my R1 last week and am looking at the 1000rr to replace it, getting a bit put off with all this talk of knocking noises). Hope the gearbox is tighter than my R1 was, that sucked big time!
 

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I have to say I am also concerned changing the exhaust. The bike is so smooth and I don't really wanna mess with the power delivery. Has anyone with a pipe noticed a difference? Or have a baseline and new exhaust run?
 

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Discussion Starter · #5 ·
The thing that makes me wonder is that when these manufacturers come out with comparison charts on dynos from stock and aftermarker pipes, it shows no dip (at least compared to stock) on the power curve. Are these legit? or is a full exhaust system the only answer to retain the linear power curve that our 1000rr have?
 

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Most dyno's I've seen show a dip at around 4000 r's and then procede to gain over stock. They butterfly value is used to change the system and allow for more back pressure at low r's. A slip-on should show a dip at low r's. Just my .02...
 

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The theory is the added back pressure will incease exhaust velocity at low RPM's for better scavenging of the cyliders at lower RPM's. Since the headers are designed large for maximum HP from the stock engine, that is how they get over the compromise.

Me personally, I plan to leave it all stock. It makes more power then I need on the street, sounds great without being excessively loud (don't want to attract attention to my daily driver), and looks better then any aftermarket exhaust I have seen for it.

EFI shouldn't make a difference with the valve removed. The carburation problems come from the pressure pulses that are inherent in the design of the engine. At some RPM's they are flowing the right way for a better air charge (why it is possible to get over 100% VE), at other RPM's that will cause the intake air to pass through the carb 3 times (intake, reverb out, then intake again) causing a very rich mixture. That is what the EFI prevents. The valve in the exhaust will not effect the pressure waves.

Those pressure waves are why exhaust lengths are so important.
 

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The theory is the added back pressure will incease exhaust velocity at low RPM's for better scavenging of the cyliders at lower RPM's. Since the headers are designed large for maximum HP from the stock engine, that is how they get over the compromise.

Me personally, I plan to leave it all stock. It makes more power then I need on the street, sounds great without being excessively loud (don't want to attract attention to my daily driver), and looks better then any aftermarket exhaust I have seen for it.

EFI shouldn't make a difference with the valve removed. The carburation problems come from the pressure pulses that are inherent in the design of the engine. At some RPM's they are flowing the right way for a better air charge (why it is possible to get over 100% VE), at other RPM's that will cause the intake air to pass through the carb 3 times (intake, reverb out, then intake again) causing a very rich mixture. That is what the EFI prevents. The valve in the exhaust will not effect the pressure waves.

Those pressure waves are why exhaust lengths are so important.
 

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Echo in here. :lol: I am actually considering the same thing of not changing the stock exhaust and work on losing weight interanlly and externally. Haven't decided no need to this bike is awesome right out the box!!
 

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This bike is great, but far from awesome right out of the box... Power is good & it stays where you put it in the corners, but it overall handles like a turd with some rather heavy steering. I'm going to play around with the geometry this weekend after I install the Ohlins shock & if that doesn't make it at least 50% better I am going to yank that HESD damper off & see what happens then.
 

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Hijack Heavy Steering

Hijacking the thread a bit.

It does steer heavy. I am getting used to it (1500 track miles now), but it does steer heavy. I rode a 636 Kawa a couple laps and then got back on the RR.... First corner I looked down to see if I had a flat tire!!!!!!!!

That was when I noticed how slow it steers. Max at Traxxion says the damper should go. I lengthened the Penske about a quarter inch and will see how that goes. I do notice the damper negatively in slow corners at high rpm on the gas exiting. It steers like a pig then. I use a lot of track.


Ernie
 

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How much of that do you think is attributed to the huge amount of trail though? According to Honda's website, the 1000RR's got 102mm! The G1K I was riding the other day had 96mm, about the amount most racers I know run. Switching between the two bikes, there was a massive difference in required force for turn-in.
 

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Running the Penske shock now with about 4 or 5 mm added length. Turn in is improved now, still slow but improved. Not sure how far I want to go here. But I prefer to raise the rear before dropping the front.

Ernie
 

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Sidewalk said:
Damn, you guys should try riding a Buell some time. You will really learn to love the light weight and agility of the RR after that!
Sure it wasnt a Schwinn trailing a wheelbarrow of bricks?
 

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Sidewalk said:
The theory is the added back pressure will incease exhaust velocity at low RPM's for better scavenging of the cyliders at lower RPM's. Since the headers are designed large for maximum HP from the stock engine, that is how they get over the compromise.

Me personally, I plan to leave it all stock. It makes more power then I need on the street, sounds great without being excessively loud (don't want to attract attention to my daily driver), and looks better then any aftermarket exhaust I have seen for it.

EFI shouldn't make a difference with the valve removed. The carburation problems come from the pressure pulses that are inherent in the design of the engine. At some RPM's they are flowing the right way for a better air charge (why it is possible to get over 100% VE)
Ahhh, volumetric efficeincy. Now there is a guy who knows a thing or two about a thing or two. Having built a few 400 HP pump gas small blocks I have to think this is sound reasoning!
 

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vigis said:
Sidewalk said:
Damn, you guys should try riding a Buell some time. You will really learn to love the light weight and agility of the RR after that!
Sure it wasnt a Schwinn trailing a wheelbarrow of bricks?
*Looks throw old pictures*

Nope, it was a motorcycle. Hell, it still is a motorcycle, even if it doesn't run, and takes up space in my garage :roll:
 
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