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Discussion Starter #1
Hey guys, I'm new to the scene. I just bought my first bike witch is a 1999 Kawasaki ZX9R. I noticed that it had a delay on the throttle response. Any help would be appreciated. And is it smart to try and keep a old bike or just save and buy a new one. I know they say to buy a used bike first for learning experience. I don't mind restoring it but is it worth it? My bike currently has 42,000 miles but this bike sounds and looks great. What is the down side of having a bike with this many miles?
 

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welcome to the forum.

Nothing wrong with having a bike with 42,000 miles on it as long as its been looked after,

you will have to be a bit more specific in your problem with the delay with the throttle response,

is it a carburetor set up on your model, or is it injected?, is the throttle cable sticking does it feel notchy when operating the throttle.

does it sound like it sucks a lot of air in but go's no where? then it picks up?
 

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With the bike being carbureted it isn't going to be as snappy as fuel injection. Try to oil/lube the throttle cable and double check that it is routed correctly.
 

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Discussion Starter #5
My ninja has carburetors and it feels like the cable is fine i have no restriction on it. Its like you can pull back on the throttle and its like the acceleration creeps up on you (a delay) out of gear runs fine but it happens mainly on first and today it kinda sputtered out at the high end of the gears. My opinion its the carburetors just don't know for sure. i'm down to fix it myself just need some guidance from my fellow Kawasaki owners. Maybe bad gas maybe some clogging in the fuel system or intake leak or restriction. Has any one had this problem?
 

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yes i have had these and many other similar problems before, not on a Kawasaki though but the principles are the same on most carburetor bikes. my problems were on a suzuki bandit 600 inline four carb set up.

the issue with my throttle delay and spluttering was due to the carburetor diaphragms being ineffective and not worrking as they should. this was because the rubber over time deteriorates, you can check it for pin holes in the diaphragm and might not find anything, you go to rebuild it and you will find that the rubber diaphragm does not sit in the circular recess in the carb body. or you might get it to go in and it bellys up in the middle as it has swelled. (this was my issue, i replaced all four and it was spot on).


however there are alot of other issues that can give the same symptoms that your having right now not knowing what experience you have in repairing bikes and what tools you have available to you lets start at the beginning things to check:-

1) check the ignition timing make sure that it is set up correctly (and check the components associated with the timing points/condenser and or electronic set up (test as per manual)

2) check the valve clearances, make sure they are set up correctly

3) check spark plugs and leads/and or coil packs for any fouling (ie oil contamination, tracking, they are the correct grade plug(i had fitted wrong grade plug before it backs fire, missfires, hard to start and makes it ride like a kangaroo wouldnt pull your cap off) check the resistances of the coil packs, checks spark plug leads for any damage cracks splits in the insulation. check the spark plugs gaps are set correctly, and set if they are all sparking bright blue(any other colour is not acceptable and indicates a fault)

4) vary rare or have i came across this problem some carbed bikes had glow plug type heaters on the bottom of the carbs to stop them icing up and help with cold starting, check these if fitted are functioning as they should.

5) some carbs had a throttle position sensor (check as per manual )

6) do a compression test make sure all cylinders are more or less at the same psi there is a +/- difference across all pots say maybe 1 to 3 psi difference for example consult the manual for these readings though.

7) put a set of vacuum gauges on the carbs to see if the carburetors are balanced as when you crack the throttle they should all work in sync if one or two carbs are out this will give you similar problems to what you are getting(if when adjusting the carbs and you cannot get them balanced its normally due to the slider sticking and thus getting back to the diaphragm i mentioned earlier)

8) check to make sure the carb fuel and air mixture screws are set to manufactures spec some carbs there is a blanking cap over the screw so you are not able to adjust the mixture due to certain country's emission laws) (there fore if you suspect they are out may be a new set of carbs or see if you can drill the caps out and adjust the screw back to manufactures settings.

9) could be something simple as its been standing that long with out being used that the fuel had gone off and blocked the jets in the carbs, and all associated fule items ie tank and fuel lies etc, remove carbs and clean with carb cleaner and comressed air blast them out make sure every thing is clean and all jet holes are clean and clear and free from blockages.. whilst your on check all settings and measures relating to carburetor functions ie, make sure the needle on the bottom of the slider is set to the correct height there are notches on the needle and a c clip to set the height, if set up wrong they can snap when rebuit, or not allow enough fuel/air to go through the carb to allow the bike to run as normal giving the same effects you have. check the float height, and condition of the needle and seat. if i was that far down in the strip down depending on cost which would out way one or other buy a set of carbs(off a known running bike from a scrap yard or buy the carb kits from your local bike supplier. the needles and jets do wear over time you can measure the tolerances to see if they are in specification, depending how much of a budget you have, replace the the whole internals of each carbs including all jets and needles seats and needles.(providing the carb bodys and recess etc are in good serviceable condition) as its quite an involved job just removing the carbs alone then to strip the carbs if this is your diagnoses ) to replace only a couple of bits to rebuild it to find you should of replaced the other bits as well (if that makes sense) ie not doing the job twice sort to speak.

kind regards

mike.
 

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Discussion Starter #7
Thanks,thats what i needed a good head start. Now that i have my list i will start with the easiest before i start checking valve clearance. I will post what i find when i find it and believe me i will find it. As far as tools i know that the vacuum is a must which i need to get on order. Any other tools that could help me?
 

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only one i can think of other than the vacuum gauges is a compression tester.

i would say vacuum gauges test and timing are the two main things to check first ,

if you post your readings on here i will try to help you further, or even if you find what the problem i would be gratful if you could let me know with pictures if at all possible as well .

kind regards

mike.
 

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Carb delay

I had a GPZ900 obviously much older than yours but, still carbed so:

I doubt if there is a fuel filter so wash out your tank with seafoam and keep it clean, make sure there is no rust in tank otherwise internal coating is needed POR-15 etc, if you dont have a clean fuel supply youll be fighting carb issues forever. Or is it a plastic tank...I dont actually know.

Sounds like a good cleaning of carbs is in order, idle/slow jets sound like the may be a bit plugged...start there. No flaming - Yamaha makes a good carb cleaner that will not harm plastic or rubber diaphragms.

The Keihin CVK carbs (they are that on that year?) have a diaphragm controlled slide, once the slide is moving smoothly - they can be modified with a vent hole to make them more reactive.

Is the ignition stock? and in good shape? if yes then ~4 degrees of advance will give it a more snap off the line and safe for a stocker

K&N filter = nice but avoid individual pods. Maybe thats not an option on this bike anyway but they are more trouble than they are worth imho.

Fuel injection more snappy than carbs, I dont know I think that is debatable.

Good Luck
 

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Discussion Starter #10
Thanks guys i appreciate the help when i find the problem i will post with pics. I knew it had to be fuel related. I will pick up some of that carb cleaner as well.
 
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