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Discussion Starter #1
So I'm Thinking of rejetting my bike for a little more power . . .gonna start fresh with new jets,needles and so on . . so what are you guys running at the moment? trying to make a chart to see what works best and what doesn't.and what other mods are you guys running?could be track or street mods.

Bike:Cbr 600f2

Main jet: 135 stock

Pilot: 34 stock

Needles: No Clips,Stock

A/F:3 Turns out.(Have No Idea Why The Bike only wants to run on this setting)

Airbox:Stock With Stock Filter


Mods:Scorch Freeflow Exhaust (Shortend),1/5 Quick Throttle,Stick Coils From Cbr 600RR,600RR Shock.
 

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JNSRacing put what he ran on his F2 in this thread but getting jet numbers together without comparing geography as well is kind of worthless. I saw a thread topic once where people were putting what jets they run, mods and geography but I cant seem to remember if it was on this forum nor can I remember what kind of bike it was for.

I have a F3 motor which is very similar and I am running the following:
the main jets are 142.5 on carbs 1 and 4 and 140 on 2 and 3. The kit also increased the pilot jets to 40 and two extra shims per needle. I backed out the mixture screw 1.25 turns

I have a K&N air filter, race header (unknown brand) into a Yoshi pipe, and live in NYC

http://www.fireblades.org/forums/honda-cbr-600/108011-after-jet-kit-install-600-f2-wont-start-run.html
 

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Discussion Starter #3
Thanks sabotage i left jeff(JNS) a message on facebook about his f2 . .. Im still waiting for him to get back to me . . .and yes i know about that post it was on cbr forum i tried searching for it but couldnt find it . . .thats why i decided to post something like that on this forum.im not going to get a dynojet or factory pro kit it wayyyy to expensive here in south africa but i can get loads of jets in different sizes for really cheap aswell as shims so i just want to get some numbers together so that i can get a starting point and then go from there.
 

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Discussion Starter #4
And i was thinking about starting off with 140's as my bike is already to lean.and im going to mod my airbox as those k&n's are also very expensive here in SA.
 

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But you already modified your air box. You drilled some holes in the top. I remember. How much are you going to mod the air box. Did you ever get a better shock than the 600rr shock you had?
 

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Discussion Starter #6
Whao!where did you come from frank?lol i dont remember you.how do you know all this stuff ?lol and yeah drilled the holes but taped them up as my bike was running waay to lean up top,so im finally gona rejet it now and nope that 600RR shock actaully rocks i made a custom mount for it so its awesome now.you got a f2/f3?
 

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Yes I have a 94 F2 and a 91 F2. I also have 08 cbr1k and 06 cbr 600rr. Anyhow, there should be a rubber divider to keep the hot engine air and radiator air from getting to the airbox intake tubes. The fairing has air intake holes and passages that directs fresh cool air through the frame on each side above the rubber divider to the snorkel tubes for the air box. Honda, I'm sure did plenty of R & D to provide the engine/carbs with lots of fresh cool air. Which allows consistent/crisp throttle response from idle to redline. Nothing wrong with changing the jets especially if location requires it but you probably aint going to get more than a horsepower or 2 from it. Alot/most of time "seat of the pants" dyno is not accurate at all. My track F2 has racing jet kit and full header system and K&N and dynoed at 86hp with a 13 to 1 air fuel ratio. Stock hp was 83ish. I remember spending all day washing and waxing my car and I swore it ran better afterwards...........but it didnt. Keep us posted.
 

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The cbr forum has a so called data base where people listed their carb jets sizes and bike mods, exhaust etc. Along with their location, altitude so on and so forth. I'm the one that explained why raising the ass end of a F2 or F3 almost 2 inches was a bad idea. I like to see your shock mount that you made. I would assume it allows a 600rr shock to keep the ass end at almost the stock height.
 

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Discussion Starter #9
Ohw yeah now i remember . . yeah i never had a problem with instability with the 2 inch lift at the back although i sid adjust it a little lower so i dont think its lifted that high anymore and it enters a courner like a champ now:eyebrows:
And yeah honestly from my point of view the f2 airbox is ****. . .cuz if itbwas good they wouldnt have replaced it with the f3 one.so im still working on the airbox as i dont just want a few holes in them i want it neat and tidy so im still figuring it out:thumb:
 

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Have you thought about cutting the top of the air box off. Just keeping the part that will bolt down to sandwich the air filter in place. I remember when I had a Suzuki GS1100 which had a restrictive air box (no where near as good as a F2 air box) and installed individual pod filters, the instructions said increase jets sizes by 25%. And it ran like crap except the top end which I was hardly ever at anyhow. So that mod was a waste of money and time unless I was drag racing.
 

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Discussion Starter #11
Yeah i thought about maybe cutting of a piece of the lid so the airbox is a tad shorter so that it gets more air under the tank and then put some mesh over it.never liked pod filters so i wont install them on any bike and that open airbox would sound awesome under that tank.but ill see once i get to that point .
 

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If you cut the top of the airbox off then you could lift the tank up a little with washers and the bigger gap between the frame and tank would allow more air into the airbox. How did you adjust the shock lower since the 600rr shock has no ride height adjustment. I'd like to see that custom bracket you made for it, if you dont mind. When you say jet kits are expensive in South Africa how much are they. I believe they're about $100 here give or take a little.
 

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Discussion Starter #13
Yeah raising the tank would work a treat as well and my 600rr shock sure has height adjustment mine is on the third setting at the moment and its not bad.i would send a pic to you no problem but i forgot to take a pic at that time. . and my rear tire hugger is on my bike at the moment so you cant see in there im gona work on the bike end of the month installing a new tire as well then i will take a pic for you.ohw and the jet kits cost about R2500 which is almost half my pay check thats about 200 american dollars and now i can get all the jets i need plus the shims and so on for about R400 and that is about 31 american dollars which is much better.
 

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You must have the only 600rr shock ever made with a ride height adjustment. Adjusting the spring preload to the 3rd setting is not adjusting the ride height. Sabotage said cylinder 1 and 4 have bigger mains than 2 and 3 but I believe cylinder 2 and 3 should have the bigger jets because them cylinders run hotter the the outside cylinders 1 and 4 but I could be mistaken. (the jets not the shock)
 

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Does anyone know why cylinder 1 and 4 has a lower velocity stack and different sizes main jets in comparison to cylinder 2 and 3?
 

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Hi and welcome to the forum ,do you have a F2 or F3 as its only the F3 that uses different sized velocity stacks, I think thats down to the F3 using DAI and the Air Flow through the filter and different Jets on 2&3 to 1&4, there's a lot of science into how the air enters the stack (y)
 
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