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Carb jets and needles

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DavidZ1R
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Carb jets and needles

#1 PostAuthor: DavidZ1R » Sun Apr 15, 2018 4:22 pm

Does anyone know the life span of jets and needles, ie 20k , 30k or what? before they need replacement, cheers.
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Re: Carb jets and needles

#2 PostAuthor: Pigford » Sun Apr 15, 2018 4:40 pm

No set mileage - pot luck with materials, fuel grade, air filtration type, riding style, etc.

But by 30k they probably will be a bit worn but not necessarily to the detriment of the bikes running?
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Re: Carb jets and needles

#3 PostAuthor: Ultim8pc » Mon Apr 16, 2018 10:12 am

Pigford wrote:No set mileage - pot luck with materials, fuel grade, air filtration type, riding style, etc.
But by 30k they probably will be a bit worn but not necessarily to the detriment of the bikes running?

I would agree. I've seen carbs that have done 75k miles with little or no wear and ones that have 20K and needed new needles and float valves.
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Re: Carb jets and needles

#4 PostAuthor: DavidZ1R » Mon Apr 16, 2018 3:34 pm

I have this shudder/flat spot below 3000 revs, I have changed the float valves, all levels good, cleaned the carbs about 4 times, the only thing not done was the needles and main jets changed, all good at tick over and above 3000 but between....... even swapped the advance unit, no joy, going to put the carbs from my z1r on see if the problem goes, if it does, new needles and main jets, its really getting on my t*ts.
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Re: Carb jets and needles

#5 PostAuthor: PAULJAC47 » Mon Apr 16, 2018 4:13 pm

David ,i have noticed the profile of some aftermarket needles is very different to the standard ones what do you have?,also did you change the needle jets?that press into the body that the needles go into? just a thought..Paul j
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Re: Carb jets and needles

#6 PostAuthor: DavidZ1R » Mon Apr 16, 2018 4:50 pm

Hi Paul, the needles and jets are the original ones, I have cleaned them in the ultrasonic bath, and flushed through, it's the last thing to be at fault., its a bugger.
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Re: Carb jets and needles

#7 PostAuthor: PAULJAC47 » Mon Apr 16, 2018 4:59 pm

David,if they are originals,may be some wear to the needle jets,not the main jets that screw into emulsification tubes,does it make any difference if you lower the needle?what notch is needle on?.flat spot you describe sounds like transition stage from pilot to main system.
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Re: Carb jets and needles

#8 PostAuthor: DavidZ1R » Mon Apr 16, 2018 6:19 pm

Well I have put the z1r on, if I get time tomorrow will give it a spin and see, will report back.
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Re: Carb jets and needles

#9 PostAuthor: DavidZ1R » Wed Apr 18, 2018 5:53 pm

Well with the z1r carbs on it runs beautiful, so the problem lies with the carbs, going to put new pilot jets in, stripped and rebuilt the slides and cleaned the needles, put all back together, flushed again , will put them back on next week, going to run out over the next few days wit the z1r carbs on, the fault must be in the prime circuit.
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Re: Carb jets and needles

#10 PostAuthor: Garry.L » Wed Apr 18, 2018 6:43 pm

DavidZ1R wrote:Well with the z1r carbs on it runs beautiful, so the problem lies with the carbs, going to put new pilot jets in, stripped and rebuilt the slides and cleaned the needles, put all back together, flushed again , will put them back on next week, going to run out over the next few days wit the z1r carbs on, the fault must be in the prime circuit.


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Re: Carb jets and needles

#11 PostAuthor: DavidZ1R » Wed Apr 18, 2018 7:16 pm

Your right Garry, just been for a quick 10 mlies, goes like a train, and sounds different with the bigger carbs, pleased the way it runs, just needs adjustment for the clunky gearbox. May have a ride out this weekend with she who must be obeyed, her first ride out for a year.
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Re: Carb jets and needles

#12 PostAuthor: King of Kings » Sat Apr 21, 2018 11:11 pm

Unlikely, Z1r’s where no quicker than the A1 in the real world!


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