900rr header installed - Wrist Twisters
 
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post #1 of 23 Old 08-19-2008, 09:33 AM Thread Starter
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900rr header installed

So I got my 900rr header with a yoshimura exhaust installation finished up last night. Went pretty well but I had a hard time getting the Y pipe out. Anyway, I rode it to work today and I'm loving it. Can't say that I really tell a noticeable difference power wise. Of course, I don't very often go WOT so it's hard to tell minor differences. There is a dramatic reduction in engine braking which I like. There is also a pretty good weight reduction which is always nice. I'm loving the sound as well. The biggest reason I did the swap is that it was a cheap way to get rid of the stink. I'm excited about the other benefits though.

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post #2 of 23 Old 08-19-2008, 09:41 AM
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well done! give us an update after a couple weeks and see if your initial impressions hold up after riding a bit.

the look of a single low side zorst can be a nice aesthetic change, black out the headers, make a little shorty can...nice little attitude shift.

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post #3 of 23 Old 08-19-2008, 09:42 AM
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hey, did you re-use gaskets or get a new set?

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post #4 of 23 Old 08-19-2008, 09:55 AM Thread Starter
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Quote:
Originally Posted by ratdog View Post
hey, did you re-use gaskets or get a new set?
I got new ones between the engine and the header. I reused the one between the can and the header because that's easy to get to if it leaks.

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post #5 of 23 Old 08-19-2008, 10:58 AM
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So where's the pics?!

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post #6 of 23 Old 08-19-2008, 12:01 PM
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post #7 of 23 Old 08-19-2008, 12:05 PM
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post #8 of 23 Old 08-19-2008, 03:50 PM
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am i the only one who has a header that didnt really fit? My D&D full system hit the round bar that is basically the motor mount. Kept the header about a quarter inch from reaching the head. I took a round tube, laid it on the bend of the brand new headers and beat all four tubes alittle with a sledge hammer. After that they went on fine. The setup i bought was for a 98 cbr900rr. I guess it doesnt have the bar in the way.

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post #9 of 23 Old 08-19-2008, 04:30 PM
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jalm, you could go to work for micron "hydroforming" their headers too !
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post #10 of 23 Old 08-19-2008, 05:11 PM
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Quote:
Originally Posted by bucky View Post
jalm, you could go to work for micron "hydroforming" their headers too !
got to be a reason they are shaped like that.

My first thought is for scavenging the exhaust out of the head by producing a suction or higher velocity flow (kind of like an airplane wing functions) than what the head produces itself. Since both intake and exhaust valves have a point where they are open at the same time, in theory it could produce a self-Supercharging effect? Provided the scavenging effect was large enough to produce such Theoretical conditions.

I know Formula One Motors are producing self-supercharging, but we don't have there millions and millions of dollars to achieve this.

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post #11 of 23 Old 08-19-2008, 08:22 PM
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Quote:
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jalm, you could go to work for micron "hydroforming" their headers too !
THats what they look like! but less flat spot .

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post #12 of 23 Old 08-20-2008, 12:38 PM
 
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I need a 900RR header

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post #13 of 23 Old 08-20-2008, 03:12 PM
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That pic is of an tri y header not a true 4 into 1 where the 4 exhaust pipes come into a collector where as the exhaust pulse from 1 tube passing through the collector creates a vacuum on the other pipes waiting for the exh valve to crack open aiding in the speedy removale of the spent gases. A tuned header has the primary tubes of equal length.
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post #14 of 23 Old 08-20-2008, 05:46 PM
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um, thanks rique? relevant to... ?

a tuned header has pipe lengths of whatever diameter/length TUNES the exhaust for efficiency in the chosen range. not necessarily all the same. it's resonance, not tape measure stuff.

dhern: everybody does. some just don't know it yet. for best results (posing, mostly) make sure you wrap it in mummy tape.
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post #15 of 23 Old 08-20-2008, 06:05 PM
 
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Will all the model year 900RR pipes fit? Any mods or is it a bolt on?

I found one on craigslist....

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post #16 of 23 Old 08-21-2008, 05:48 AM
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Tuned-length primary tubes for maximum exhaust scavenging and velocity
Mandrel-bent tubing for smooth exhaust flow
Light weight & sturdy 18 gauge tubing
Long transition collector for decreased back pressure
5/16” machined flanges for a perfect seal
Industry’s best welds for durability
Designed for optimal performance
All necessary hardware included for a complete installation
Info from from hooker maybe you can call them and correct them Buck.on there site they semm to make big deal about equal length primarys maybe they need some humility.

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post #17 of 23 Old 08-21-2008, 05:54 AM
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96-98 cbr 900RR headers fit

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post #18 of 23 Old 08-21-2008, 06:03 AM Thread Starter
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Quote:
Originally Posted by dhernb11 View Post
Will all the model year 900RR pipes fit? Any mods or is it a bolt on?

I found one on craigslist....
My understanding is that 93-99 all fit. But, the 93-96 has a slipon muffler and the 96-99 is bolt on so you can't combine a 93 header with a 99 muffler. I think mine was a 98 and it fit very well.

The stock 900rr header just bolts on the bike. You do need to fabricate a bracket to mount the muffler to the passenger footpeg. Not very difficult at all. I followed the instructions posted by ratdog in this thread

https://www.wristtwisters.com/forum/s...=900rr+exhaust

The only part I struggled with a bit was getting the old Y pipe out. I didn't have a good way to jack the bike up as high as it needed to go. I ended up taking both bolts from the shock out. If I get a chance I will snap some pictures of my mounting bracket.

Some guys do weld another bracket on the header that bolts to the bottom of the engine to provide a little more support and reduce vibration. I haven't decided if I'm going to do that.

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post #19 of 23 Old 08-21-2008, 07:25 AM
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The stock head pipes from Honda seem to fit. Aftermarket headers may just bolt on. My vance and hines SS2R system needed the pipes peened just a little bit to keep them from ratteling on the cross bar. It seemed like they fit fine but there was a buzzing sound when it was running. It cost me another set of exhaust gaskets to fix.

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post #20 of 23 Old 08-21-2008, 12:56 PM
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ricque, you debate oddly. there's no mention of equal length in your side of the debate that you cut and pasted. so your argument doesn't support your contention.

from wiki, which isn't the authority on tuned headers, but it's correct:

"Headers are generally circular steel tubing with bends and folds calculated to make the paths from each cylinder's exhaust port to the common outlet all equal length (and they're not talking about tuned headers yet) , and joined at narrow angles to encourage pressure waves to flow through the outlet, and not back towards other cylinders. In a set of tuned headers the pipe lengths are carefully calculated to enhance exhaust flow in a particular engine revolutions per minute range. (and it doesn't say equal length is part of the deal) "

(my words now) in fact, the header tube VOLUME is more important than length alone, which is one reason why you see stepped tubing in some applications. it's also why tough-to-package engines may use a short fat primary or a long skinny primary: they're nearly identical in volume and it all matters what packages best. also, notice that many bike's intake velocity stacks are unequal length. that too is "tuning" in the EXACT same sense as tuning headers.

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post #21 of 23 Old 08-21-2008, 03:27 PM
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Quote:
Originally Posted by timbo813 View Post
My understanding is that 93-99 all fit. But, the 93-96 has a slipon muffler and the 96-99 is bolt on so you can't combine a 93 header with a 99 muffler. I think mine was a 98 and it fit very well.

The stock 900rr header just bolts on the bike. You do need to fabricate a bracket to mount the muffler to the passenger footpeg. Not very difficult at all. I followed the instructions posted by ratdog in this thread

https://www.wristtwisters.com/forum/s...=900rr+exhaust

The only part I struggled with a bit was getting the old Y pipe out. I didn't have a good way to jack the bike up as high as it needed to go. I ended up taking both bolts from the shock out. If I get a chance I will snap some pictures of my mounting bracket.



Some guys do weld another bracket on the header that bolts to the bottom of the engine to provide a little more support and reduce vibration. I haven't decided if I'm going to do that.
My '95 900RR header has the three bolt muffler attachment.

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post #22 of 23 Old 08-21-2008, 04:40 PM
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I luv you Buck Tuned-length first two words

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post #23 of 23 Old 08-22-2008, 10:28 AM
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this is what i'm talking about ricque: you argue MY points !
"tuned length" is not "equal length" and you were saying it is.

a tuned piano doesn't make the same note 88 times. but it also makes none of them by accident. each string has a different length.

tuned means tweaked with an attempt to improve performance, it doesn't mean "to make universal or identical in length".

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