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CBR 600F2 1991 - 1994 CBR 600F2

Needlesssssss

  #1  
Old 01-06-2019, 07:11 PM
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Hey it's me again lol
been trying my hand at tuning this 91 f2 for what feels like eternity. I've been shimming stock needles, removing shims, etc. I don't wanna buy an entire jet kit whereas I have bigger jets in it for the slip on. My only other guess would be the profile of the needle not working like I want.

Pulls great off idle and top end is smooth, problem is the in between, where it changes from pilot to main jet, gets a little fluttery or gurgling. Should I keep playing with shims or bite the bullet for jet kit.

TIA
 
  #2  
Old 01-09-2019, 01:09 PM
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I would go for a kit.. dynojet stage 1 is a great drop in kit thats works great..
 
  #3  
Old 01-10-2019, 08:00 AM
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Originally Posted by JacobG13 View Post
Hey it's me again lol
been trying my hand at tuning this 91 f2 for what feels like eternity. I've been shimming stock needles, removing shims, etc. I don't wanna buy an entire jet kit whereas I have bigger jets in it for the slip on. My only other guess would be the profile of the needle not working like I want.

Pulls great off idle and top end is smooth, problem is the in between, where it changes from pilot to main jet, gets a little fluttery or gurgling. Should I keep playing with shims or bite the bullet for jet kit.
TIA
For just a slipon, you shouldn't need bigger jets. That is probably your problem.
Bigger jets are probably making it to rich in the mid/upper range. Shimming the needles fix the upper range. But it's still too rich in the middle.
If you've got the stock jets, put them back in.
 
  #4  
Old 01-12-2019, 06:18 PM
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Well I've been chasing the issue the whole time I've had the bike. Tried the stock setup tried what feels like 1000 different variations. So I ordered a 6sigma jet kit. I'm gonna tear them all the way down an clean em good. Has anyone had this kit an had luck with it. Also I need y'all to talk me out of running open headers. I know it's bad but so tempting
 
  #5  
Old 01-14-2019, 06:16 AM
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I never ran that jet kit.. i always used factory or dynojet.. if you want a chance of it running right keep the muffler on it..
 
  #6  
Old 01-18-2019, 06:25 PM
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Duely noted.
So I got the jet kit in yesterday, and no needless just jets and shims. I'm still gonna break em down an clean em, hopefully find the problem there. Also noticed last time I rode she ran great until she warms up then starts popping an Carrying on.
 

Last edited by JacobG13; 01-18-2019 at 06:26 PM. Reason: Spelling
  #7  
Old 01-18-2019, 08:43 PM
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You absolutely can not tune dirty carbs. You need to clean them first...really clean, then clean them again. Blow dry with compressed air.

If you are tuning by the seat of your pants, you're still just guessing.
And it can take forever to guess right.
You really should take it to a dyno and run it with an A/F graph.
That will tell you exactly what you need to do to get it to run right.
And yes, tuning a bike costs a lot more than just throwing a jet kit at it.

As for open headers. I was going to ignore that, but since I'm here now.
I can think of at least a dozen reason why doing that is a really bad idea.
I can list them if you really want, but I think you get my point.
 
  #8  
Old 02-05-2019, 05:29 PM
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Update:
so it took a couple days but I got the carbs broke all the way down (slides,bowls,jets,choke) cleaned em. Then cleaned them again. And one more time so I could sleep at night, took compressed air to all opennings (every hole gas or air goes) . Got them all together and back on the bike, threw some gas in the tank. Turn key.......... nothing.
come to find out I accidentally swapped the wires for coils on right side, lol honest mistake. Changed plugs and took off coils (was cleaning up frame).
fired right up after I fixed my mistake.
so far she runs good, at temp slight popping but not till comes down to lower rpms. Still have to synch them again but as for now I am ecstatic.
maybe play with mixture screw a bit but the hard part is over lol
 
  #9  
Old 02-06-2019, 11:51 AM
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Good work. Cleaning the carbs isn't hard, just tedious and they do have to be really, really clean. The popping is from being too lean. Get them in sync and then adjust your A/F mixture and you should be GTG.
 
  #10  
Old 03-18-2019, 06:20 PM
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Got the carbs synchronized, put in a filter for the sub air cleaner (talked about in seperate thread) mixture screw 3 turns out. No longer pops on deceleration, however under heavy acceleration it gurgles(pops) only for a second then climbs up the revs. And while holding throttle (cruise) I can hear the faintest popping. If I were anybody else I'd leave it an ride the **** out of it, however I feel I am too close to quit. Any idea
 

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