hi ,
i have a 1995 zx9r ive just bought, and its idled real rough.
so i changed the spark plugs but didnt change anything.
then next i got the carbs balanced, it seemed better for a very short time now it doesnt run.
it turns over fine just doesnt fire up at all.
what could my problem be?

 

Welcome to KF

A few questions: What other history on the bike? Did it sit for any time frame? Did you bump the kill switch and not knowing it while you were concentrating on the other issues?

 

yes it was sitting for about a year and a half i think before i bought it.
what kill switch are you talking about, the one you need to be on run to start? no that is where it should be.
i just figured out that the spark plugs seem to have a problem. it took out one from each pack then earth them onto the motor and they dont spark, but if you hold them up a little bit the spark onto the motor, thats the wrong way round isnt it?

 

and i checked to see if there was fuel in the lines before the carbs and yes there is. maybe when i got the carbs balanced he might have made it so there is to much fuel going through and flooding the spark?
is that possible?
and i have only owned it for two months so dont know the history of the bike.

 

Back to basics. If it's been sitting, clean the carb jets (manually; don't try to put seafoam or other "cleaner" in it...doesn't work that way.) Fresh fuel. 9's will varnish-up after a couple months of sitting. Sounds like you're getting spark; what did the old plugs look like? Choke working properly? Might also try draining the carb bowls (using drain screws) and letting them refill after turning on the petcock, to get an even flow for consistent float height. If you have fresh fuel, clean jets, good spark, you shouldn't need any starting fluid, so don't be tempted. Starting fluid is hard on the rings over time, if you get into the habit of juicing-it to get started.
My vote is plugged carb jets....
Report back. (Excellent bike, btw. It won't win any GP's by today's standards, but an absolute bullet-proof sporty commuter if you keep up with maintenance and don't abuse it.)

 

ok mate thats progress then. can you tell me what i need to do to clean the jets as i am a novice to motorbike mechanics. does it have it in the haynes service manual im going to get one this week. do i need to take the whole carb right off the bike? a quick step by step would be awesome and needed. thanks. danny

 

I am not a haynes manual nut, I prefer the factory service manual. The carb rack does need to be removed to do a good cleaning. If the carb boots are stiff, this makes things difficult to remove and re-install the carb rack. Things are pretty tight.

 

Watson, before you pull the carb rack, (because I KNOW what is involved) you said "it ran better for awhile." Define "ran better." Has the brain box (on the rear fender) been swapped, cut, or otherwise fiddled with? Some aftermarket boxes (Vance & Hines) just don't work on this bike (even when checked by the factory...but that's another story.) All wiring, plug leads, ground, etc. tight and right?
You don't need a manual for cleaning your jets; just basic tools. You will need a long and short Phillips screwdriver, (if memory serves) one or two 8mm and 10mm wrenches for the throttle and choke linkage, pair of pliers for the fuel line hose clamps (unless someone installed real hose clamps...in which case a slotted screwdriver or probably 8/10mm socket), a 10 or 12mm socket for the fuel tank front/rear brackets, and a slotted screwdriver that FITS the slot on the jets. Don't wonk-around with one too small and make a mess of the slots. They're brass. You'll also need a very thin piece of stiff-ish wire. A small magnetic parts tray can come in handy unless your work space is clean and clutter-free. Public safety disclaimer: no smoking.
As for the carbs, undo the throttle and choke linkage (at the carbs.) Loosen the rubber carb boots. Pull the carbs straight back (may need to wiggle up and down a bit.) Unscrew the carb bowls (on the bottom of the carbs). I tend to prefer one at a time so I have only what I am working on to keep track of. You will see "brass-looking slotted screws" in the center, looking upward between the floats. Gently unscrew those (maybe tap your screwdriver just to help that initial "stuck" feeling.) Take a very thin wire ( I like stainless safety wire) and poke through the tiny holes to get the boogers out. Repeat for each carb. I like to dip with alcohol or brake cleaner, (which does not leave residue like a degreaser can) and wipe dry. Double check your bowl gaskets upon reassembly, and don't ridiculously over-tighten the screws...(again; use the correct size screwdriver) there's probably a torque spec. I like about 1/8th turn past snug. Re-install. (Now is the perfect time to install an inline fuel filter between your tank and carbs. Yes; I KNOW there's a screen inside the fuel tank. Trust me.) FRESH GAS. Turn on the petcock and give it just a few minutes to fill the bowls. Turn on the key and hit the magic button.
Report back. If that doesn't do it, we move down the list.

 

ok ive had the carbs off. took the bottom covers off and found they were clean as a whistle. so as i had that off i checked the fuel filter and there was some goo in there and blew it clean (have to get a new one tomorrow).
if there was some goo in the filter will there be some in the pump?
the pump was pulsing so that must mean it works aye?
so i put it all back together apart from the air box turned it over and still nothing.

im more concerned about the spark plugs.
are they meant to spark when you test them against a engine bolt or when its just above the bolt or does it not matter too much about that?
what is left to test? compression?

 

Compression, timing, electrical system integrity. When it was "running rough," was it backfiring, any severe knocking sound or cam chain whine, flooding the plugs? How many miles are on the bike? Have you taken the top cam cover off to spec the valves and check condition of the cam chain? What does your oil look like?
It's good you checked the carbs; not a wasted effort. You can cross them off the list. Any local bike buddy mechanics you know?