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Discussion Starter #1
I just rejetted my F4 last night. After installing my Yoshimura Competiton Pipe and K&N filter, it was sluggish up to 5500. It was beginning to get on my nerves, and even though Yosh said no rejetting req'd, I bought a Factory® Config. 10 kit. K&N said it was a good thing to do.

I still have a little bit of adjusting to do, but I'm fairly good with carb & engine work, so I should be alright.

To get to the point though: I took it out last night after installing the kit and doing the initial adjustment to see how it would run. This of course after I reassemble most of my bike and forgot to turn the fuel back on (duh :D). Anyway...I decided to ride without any fairing to save some time. I took it out and immediately noticed it ran lean below 6500. After that the midrange rush was stellar. I took it on the interstate and this is where things became REALLY interesting. I was cruising along at about 80mph when I decided to do a 6th gear roll-on, you know...see what kind of response I was getting. I did so and was pleased with the results.

The amazing thing though was that at about 120mph (around 10,000 I believe) the bike started to bounce the front tire off the ground. I mean it literally pulled the wheel off the ground about 6inches then dropped it again, then kept up with these little 3inch bounces. I was friggin' astounded. There wasn't any wind or anything last night either.

I know 600's are powerful, but that was crazy. Anyway, I can't wait to get home from work today and see what it can do on the low end once I raise the floats and adjust the fuel mixture screws.

I've heard a bunch of people say that rejetting did nothing for them, but it certainly helped me. I'd be interested to hear anyone else's "rejetting tale" and how it helped/hurt their performance.

P.S. Just to clarify. I WAS in 6th gear. Not a mistake. UNbelievable I know...

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~Nick
2000 CBR600F4
Piped, Jetted, totally trick...
Keep the Rubber side down
my Bruthas AND Sistas!!!
 

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I am having my R6 2000 jetted this Tuesday. She already has a yoshi slip on pipe. I will also have it dynoed next Saturday to see what gains it has if any.

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I REALLY hope the weather is good Sunday so I can witness this freakishly powerful F4 firsthand. Say Nick, did you also change your front sprocket to a 10 toother?

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'98 Superhawk
 

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Discussion Starter #5
Yeah I know how much it sounds like I'm making this up, but I'm really not. I guess it's possible that a strong wind came right at that moment and lifted the bike a little, although that would be a first for me.

Either way...it happened, and even if I can't repeat it, the difference in acceleration is still there. Now it's just a matter of keeping the top end while adjusting the bottom end. Theoretically, they don't affect one another in any way, but that's in a perfect world, and we all know... :D

The bike is basically stock, and no, there haven't been any gearing changes. You can see the complete specs in the "How Do I" forum.

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~Nick
2000 CBR600F4
Piped, Jetted, totally trick...
Keep the Rubber side down
my Bruthas AND Sistas!!!
 

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Yes, it almost sounds unbelievable for a roll-on in 6th. When I rejetted my bike, the performance below 4K suffered, but mid to topend was very noticable...in a good way.

Trevor

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It doesn't matter if it comes up in 6th!! The only thing that matters is that it DID improve on the performace. :D :D :D

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Dan F4 Red/Black
 

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Yo' Brutha,
you putting the bike on a dyno anytime soon??
i'm sure alot of people here would be interested in knowing what kind of numbers the bike is putting out.... :)

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arif
'99 F4
 

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Discussion Starter #10
There is a brand new Harley/Buell shop about 15 minutes away which will run it for me for $30. If I can get it up there before I leave for Summer term at college (July 7), I'll post the numbers. If not...it will have to wait until September. I'm sure I'll still be here then though. SO if you have the patience... :D

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~Nick
2000 CBR600F4
Piped, Jetted, totally trick...
Keep the Rubber side down
my Bruthas AND Sistas!!!
 

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I can see this as being very possible if the rear suspension had been softened up like a dirtbike to allow for some serious sag on throttle.

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little more lean, little more, little, oh shit.
 

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Discussion Starter #12
I have tried to repeat this, and I am now reserved to believe that there was a sudden wind right in my direction that picked the bike up a little bit. There have been no suspension mods, because I LOVE the stock settings. Anyway, I think - and it makes sense- that this was a one time thing never to happen again without the aid of a strong headwind. Oh well. It still wheelies like a mad b--ch without even tugging on the bars, and I like that a LOT! The power delivery is amazing now. I have even tried laying on the tank to keep the front wheel down...it won't do it. come up around 7,000. Kewl...!!!

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~Nick
2000 CBR600F4
Piped, Jetted, totally trick...
Keep the Rubber side down
my Bruthas AND Sistas!!!
 

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What elevation are you jetting for? Which jets did you use/float settings/air screw settings/ect.? I live at about 6000 ft. and just recently had it over 10,000 ft. and the bike would not run below 6k RPMs. It is so rich on the bottom end that it sounds like the engine isn't even turning over.

In Colorado Springs at 6,000 ft. I can definately feel some flat spots in the powerband. Does anyone know of a dyno in the Springs or surrounding area? Harley Shop/Performance shop/ect.? I would like to jet it and put on a slip on. Later I may upgrade to a full system, but now I want smooth power for the stock setup.

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Discussion Starter #14
I posted all the specs in the "How Do I" forum under" 2000 600 F4 rejet specs". That should be what you need. Lemme know if you want more. Good luck!

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~Nick
2000 CBR600F4
Piped, Jetted, totally trick...
Keep the Rubber side down
my Bruthas AND Sistas!!!

[This message has been edited by CBR Brutha (edited June 21, 2000).]
 

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Taner, Nick lives at under 1000 ft elevation, so I don't think his settings will help. Try to find a local with an F4. Worst case scenario- buy a jet kit and use their phone support to help dial it in.

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'98 Superhawk
 

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Discussion Starter #16
...If you're gonna rely on phone support, don't buy a Factory® kit. Their phone support absolutely sux. Thought this might be useful...

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~Nick
2000 CBR600F4
Piped, Jetted, totally trick...
Keep the Rubber side down
my Bruthas AND Sistas!!!
 
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