hi, names steve. got a 99 zx6r with full muzzy. heres the deal, it would beat my buddies o3 r6 no prob and pull on him with stock exhaust. put on full muzzy. he pulls on me now. i tried dynojet jet kit, would not run right with any jet or needle clip combos. put back in stock stuff and ordered factory jet kit. tried factory kit and still cant get rid of hesitation/dead spot around 5000-6000 rpm. originally had 137.5/140 mains. right now has 135/137.5 mains. cant get rid of dead spot at all. worse when really hot. plz need help, been trying for like a week to get this bike straghtened out. thnx in advance for help! oh yea, mixture screws out like 2 and 3/4. got good top end around 8k and up rpm, and good from 0 to about 4800 rpm. factory pilot jets installed out of kit, i think 17.5.
jetting help 99zix6er
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instead of using factory or dynojet kits i think you might want to check out ivans jet kits they seem to be the most popular, and alot of people would swear there the best out there.. other then that best you can do is play and swap till you find what works, good luck 
Steve,as a starter, if the midrange hesitation is getting worse as it gets hot it indicates a rich condition for the mid. I have the same setup as you with the Dynojet kit at the standard settings with none of those problems(I am at sea level though). Not sure if the jets you have installed correspond size or # wise to the jets you pulled out.If they are comparable it appears you would have leaned the bike out more and that wouldn't make sense after installing a full exhaust. First a few questions though.
1. Have the carbs ever been jetted/modified before you?
2. Are the carbs clean?
3. Did you synchronize the carbs after you were done jetting?
4. Did you check the float level.
IMO these should be the first things for you to check no matter which jet kit you use. I would go with the jet kit manufacturers suggested settings. As for the possibly rich condition, lowering the needle a smidge might help the flat spot. Keep records on what mods you do and how it affects the bike so you can keep track of where you are and where you have been in the tuning process. Be patient, consistent, and meticulous in your changes. Let us know how it goes.
1. Have the carbs ever been jetted/modified before you?
2. Are the carbs clean?
3. Did you synchronize the carbs after you were done jetting?
4. Did you check the float level.
IMO these should be the first things for you to check no matter which jet kit you use. I would go with the jet kit manufacturers suggested settings. As for the possibly rich condition, lowering the needle a smidge might help the flat spot. Keep records on what mods you do and how it affects the bike so you can keep track of where you are and where you have been in the tuning process. Be patient, consistent, and meticulous in your changes. Let us know how it goes.
remember that jetting is determined by throttle position, not by engine speed: http://www.motocross.com/motoprof/moto/mcycle/carb101/carb101.html
ok, set floats to 9mm tonight instead of 10. 10 seemed a lil drastic.nehow, ive got 17.5 pilots, 135/137.5 mains, needle on 3rd slot down from top right in middle. mixture screws about 3 turns out. the old girl is alot better in the 5k-7k area, not a dead spot at least, seems a lil sluggish tho. i started out tonight with the needle on the 2nd slot down and it felt "dry" around 5k-7k so i raised it one notch. so now shes jus a lil sluggish around 5-7k. tomarrow ill try one more notch down to see what happens. if its too much, maybe ill put it back on notch 3 and then put a small shim under needle to raise it "half" a notch. u guys are deff. awesome help and i really appreciate all the help. this is deff the best damn site i think ive ever run into. my girl just got an 06 636 and i finally got to ride it. damn im jealous, lol.[}]
]well, with 9mm float height, 135/137.5 mains, about 3 out on mixtures and 3rd notch down on needles seems to be the best ill get. good low and top, 5-7k there but kinda leaves something to be desired. rode the 636. i want fuel injection,lol. at least i can power wheelie 1st gear by just going from a dead stop and not havin to chop off the throttle. now the test is to see if i can beat my buddies 03 yamaslow r6. [:M110]
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