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Discussion Starter · #1 ·
Ssup guys,

I'm facing a peculiar problem. My ninja stutters in the low rpm's. As in regardless of the throttle im applying it takes its own sweet time picking up the pace, the whole time as thought there isn't enough fuel flowing through. BUT this is only till it hits about 3000 rpm..beyond that its perfect - flies like a bird.

I have the FSM. Im guessing its the fuel filter. Right? it has to be clogged.
Incase u were wondering its a 92 ZX7
 

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Check in following order:
Pilot air screws - are they set right amount of turns out & are the rubber 'O' rings okay?
Air leaks around inlets (spray easystart or WD40 around them when ticking over) if it picks up momentarily there is an air leak
Carb balance (have valve clearances been done recently, if not do these before carbs)
Blocked pilot jets (most likely if bike has been stood unused a long time) check for crud/gunge or water in the carbs & fuel filter(s)

HTH
 

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Discussion Starter · #3 ·
It has been lying unused for a long time! Thats how I got it for a real steal. :)

Thanks for the info. Will check all asap and post the results.
 

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Should add that the carb balance ought to be the last job to do after cleaning carbs.

It probably is blocked jets. It will pay to strip the carbs completely & give them an overhaul. What happens if a bike is stood is that petrol evaporates from the carbs & also seeps through the petrol tap & in the end leaves a gungy deposit in the carbs which can be difficult to shift. If it is bad it will pay to flush your tank out as well and add half a tin of STP fuel cleaner to the first couple of tank fulls just to make sure.
 

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Good advice given, take the carbs off and clean them, set the valves, then balance the carbs. Good luck!
 

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most 7's are like that becuase of emmisions control a bit boggy, there are some mods you can do to achieve a better response , without spending any money
 

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Not to jack your thread but Im having the exact problem with a 87 zx7r :banghead , I have taken apart and cleaned the carbs twice, set float hights, replace fuel filter, and started by setting air/fuel mix 2 turns out and then went 1/2 turns out till i got 4 full turns out with no luck (way too rich at an idle) I then started shimming the needles 1 shim at a time (with air/fuel at 3 turns out as it seemed OK there) untill i got to 4 shims and the low end studder is still there :eek:hno (mids and high rpm are perfect at 2-4 shims)

I think im having a problem with the slides, someone drilled out the air passage beside where the needle is and Im not sure what size it suppost to be. I filled it in and drilled it out to a 5/64 hole but im not sure if that allows enough vacuum at low rpm to raise the slides?

I should also mention that ive got #135 main jets in it right now and its got an aftermarked 4 into 1 full exhaust with individual K&N's
 

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Discussion Starter · #9 ·
Well, I just handed the bike over to my mechanic for fitting a new exhaust. He'll do the cleaning/tuning etc..so will let you know if things are better
 

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Discussion Starter · #10 ·
Well, the bike isn't back but I did check it out.
The accelerator cable was screwed, so had that replaced.
Tuning is ofcourse needed, but the carbs were pretty messy. Had them cleaned and the jets as well. Seems a couple of the cylinders might not have been firing at all (for some time atleast)
and the idle cable is damaged - have to get that changed. More reports soon.
 
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