250r carb problems?

[ManiacMack]

having issued getting a 03 ninja in tip top running shape, its acting like the carb is clogged, ive rebuilt it 3 times and just broke it down again last night, it looks super clean on the inside and the jets arent clogged either, what else could be the issue when it bogs down around 600 rpm-1k rpm? idles fine

[jkv45]

Originally Posted by ManiacMack

having issued getting a 03 ninja in tip top running shape, its acting like the carb is clogged, ive rebuilt it 3 times and just broke it down again last night, it looks super clean on the inside and the jets arent clogged either, what else could be the issue when it bogs down around 600 rpm-1k rpm? idles fine

It should be idling at 1300, so I'm not sure what you mean.

The Pilot Jets and the idle mixture screws control the fuel flow at idle and slightly above. If that part isn't operating properly it would be the first place to look.

The idle mixture passages need to be cleaned carefully, and the screws should have a spring, washer, and o-ring on them. They should be set to 2.5 turns out as a good starting point. The Pilot Jets also need to be completely clear. There's also a possibility that something isn't assembled correctly.

There are plenty of other things that can also effect performance in that range, but those are the basic and most obvious.

[csmith12]

Tears in the diaphragm
Improper reassembly
Vacuum leaks
Carb boots not sealed (normally on the airbox side)
Floats out of adjustment
Wrong jetting
Debris in airbox
Water in fuel
Petcock not letting enough fuel through
Clogged fuel filter
Valves out of spec

That should get you started.

[ManiacMack]

sorry, 6k and 10k.....ill be able to give more details later today, im at work right now

[Just_george]

I just had the same issue with my 09 250r. I took the carbs apart cleaned them put everything back. I still had the same issue, took them apart again found out I ripped the diaphragm. I replaced that, put a washer under the needle in my stage 2 dyno jet, and cleaned the petcock filter, and set the adjust idle mixture screw at three turns out. Put everything back together now she sounds better than before!!!

[ManiacMack]

last time i rebuilt the carbs, i cleaned everything as thorough as i could, i have no compressed air so getting the smaller passageways are a little bit harder, im curious and hope that there is just a large blockage that im just not finding, when i broke the bowls down i expected to see some debris there but even under the jets and inside of them all were spotless, when looking for tears on the diafram, i didnt see any last tim when i broke it down but i used carb cleaner to clean it out, do i need to look for microscopic tears? how do you know if a carb needs to be syncd? its all factory and there are no shims for the needles, the vaccumme boots are fine, im about to change the plugs. i thought it could have been bad gas so i drained the tank and made sure there was fresh new gas in it, the petcock filter was clean, did i miss anything?

[jkv45]

Originally Posted by ManiacMack

last time i rebuilt the carbs, i cleaned everything as thorough as i could, i have no compressed air so getting the smaller passageways are a little bit harder, im curious and hope that there is just a large blockage that im just not finding, when i broke the bowls down i expected to see some debris there but even under the jets and inside of them all were spotless, when looking for tears on the diafram, i didnt see any last tim when i broke it down but i used carb cleaner to clean it out, do i need to look for microscopic tears? how do you know if a carb needs to be syncd? its all factory and there are no shims for the needles, the vaccumme boots are fine, im about to change the plugs. i thought it could have been bad gas so i drained the tank and made sure there was fresh new gas in it, the petcock filter was clean, did i miss anything?

It bogs at 6000 to 10,000 - but at what throttle opening? Carb issues are best diagnosed by throttle position.

At WOT the fuel metering is done by the Main Jet, so that would be the one to double-check. It's also going to effect the fuel metering almost everywhere above about 1/4 throttle or slightly less. Shimming the needles is a common mod to get smoother mid-throttle operation, but at WOT it's not going to be a factor.

[ManiacMack]

ive tried taking off at full throttle and ive also tried easing into it aswell, after it gets past that bogging down part it goes back to normal, should i take the main jet apart from the jet housing? (not sure what its called but the jet can be taken apart farther) ive rebuilt 250 carbs before and successfully about 7 times? in my experience i tend to overthink things

[ducatiman]

yes, the "main jet holder" aka emulsion tube....you need to assure the holes (if present) are clear

the needle jet (commonly known as a "collar") resides underneath, be certain it is present and clear, its visible looking into the venturi note it only fits in 1 direction.

you removed the needle? Checked taper for corrosion or debris?

Did you leave any components loose? Assemble anything incorrectly?

Its bogging ALL THE WAY from 6 to 10K?

[jkv45]

Originally Posted by ManiacMack

ive tried taking off at full throttle and ive also tried easing into it aswell, after it gets past that bogging down part it goes back to normal, should i take the main jet apart from the jet housing? (not sure what its called but the jet can be taken apart farther) ive rebuilt 250 carbs before and successfully about 7 times? in my experience i tend to overthink things

I would check the Main Jet, emulsion tube, and Needle Jet (collar) for condition and correct installation. We have seen instances where the Needle Jet (collar) has dropped out unnoticed, and wasn't installed.

There may also be an issue with the diaphragms or vacuum passages.

[ducatiman]

no sense tag teaming ....i'll bow out, its all yours jkv.

But note we are on the same wavelength.

[ManiacMack]

i dont care if you guys tag team at all, i need help! hahaha...no abnormalities aka pitting, corrosion, ill double check the jets when i get home and i can also post some pics of the condition of everything, yes it bogs 6-10k the whole time
everything was put back together properly and snug, not too tight, all parts were included

[ManiacMack]

btw i let the bike idle untill it gets to operating temperature to test the ride, when i get the choke set for the bike and i dethrottle at a stop, the bike reaaaaly wants to die

[Ghostt]

Late to the party, but I'm here, and I see your relatively close to me, maybe a road trip is in order.

Another thing to add is a valve adjustment, or at the very least checking the clearances.

[jkv45]

Originally Posted by ducatiman

no sense tag teaming ....i'll bow out, its all yours jkv.

But note we are on the same wavelength.

I feel like it has pretty much all been covered.

Soooo many carb-related threads going it's hard to keep them all straight. Most of the people should just pack them up and send them to you so they could get back riding a bike that runs right.

No disrespect to the OP, but most people are positive that they have cleaned everything thoroughly and assembled it properly, but later find out it's not the case.

Cleaning, adjusting, and tuning Ninja carbs is an art!

[Ghostt]

And having the proper equipment to do them is also just as important as knowledge. Equipment like ultrasonic cleaners, soda blasting, etc...

Ducatiman just did mine, and I've also tested a set of 32s for him, both are simply top quality products once he's worked his magic on them.

Keep in mind that I had no obvious issues with my carburetors, the ran, and ran good, but given the age of them 18 years, it was time for a refurbishing.

It says a lot when you get them back, bolt them on, prime the carburetors, and it's starts on the first try, no drama, setting the idle is the only thing that has to be done.

I have always recommend his services.

Before pictures



Afterwards

[ManiacMack]

i get the whole overlooking thing and people think they have the carbs rebuilt properly, i have access to 3 ninja 250's and have done the carbs on 2 of them. its running into a option for me of not being a carb issue, i want to make sure that i have covered everything about building this so i can rule it out. could a loss of compression give the same effect? i would think it would run like crap during idle if the compression was lost, the way the rider explained the issue when it failed was "it felt like i blew a sparkplug out of the head", was riding high rpm's on the interstate and that happened. the bike sat for like a year or more after. i checked the plugs first and both were there, threads were fine, it felt exactly like a fuel issue when i jumped it off, if anyone knows 7oxsin its his old bike im trying to fix so he can sell it (im his brother)

[Ghostt]

I'd check the valve adjustment, if those are out of spec, your fighting an uphill battle.

[ManiacMack]

i have NOT seperated the carb, i dont know if that is necessary to fully clean it, if im wrong please tell me because the only thing that i think is going on here if its a carb issue is a hidden blockage in a 90 degree passage or something, i took speaker wire cleand each hole in the main jets and the idle jets and where the passages lead to i tried to poke the wire through the passages but it was too soft, im currently in the process of getting some guitar string and trying to get it threaded through some of the passages to make sure there isnt a major blockage

[ManiacMack]

Originally Posted by Ghostt

I'd check the valve adjustment, if those are out of spec, your fighting an uphill battle.

the ticking on this particular ninja is a little louder than some others but im chalking that up to old oil and possibly a stretching (cam?) chain

EDIT: epa screws are still leaded over, no adjustments made to them

[jkv45]

Originally Posted by ManiacMack

the ticking on this particular ninja is a little louder than some others but im chalking that up to old oil and possibly a stretching (cam?) chain

EDIT: epa screws are still leaded over, no adjustments made to them

When the carbs are off, remove the caps and the screws. Clean the passages thoroughly and check that both the o-rings are intact. Set the screws to 2.5 turns out.

This shouldn't make it run different in the 6000 and up range, but it's just a good idea to make sure it's clear and be able to make adjustments to the idle mixture later.

Are both pipes the same temp? Are both plugs the same color? Have you looked at the cams and rockers for damage?

There may be other issues besides the carbs.

[ducatiman]

Originally Posted by ManiacMack

EDIT: epa screws are still leaded over, no adjustments made to them

You insisted "I cleaned my carbs".....

if the above is the case you DIDN'T. Its IMPOSSIBLE to clean the entire pilot circuit omitting pilot screw removal, coupled with compressed air MINIMUM is essential....pilot metering tip cleaning and automatic replacement of the tiny oring as well.

Now, i must question what action was taken on the float system....automatic replacement of float valves and fuel level setup. Any?

[ManiacMack]

ive just been doing a parts replacment, i made sure to keep the pieces that came off going right back where they came, i dont know about the float valves, i was never taught about carbs...earlier i was reading about the float depth but they were talking about bending the little metal flap on the float (i didnt do that) should i drill out the lead caps and clean it through that way? i dont want to get too much over my head, im very competent, but my professional focus has been cars so far, and the work on bikes have just been personal and family

[jkv45]

Originally Posted by ManiacMack

ive just been doing a parts replacment, i made sure to keep the pieces that came off going right back where they came, i dont know about the float valves, i was never taught about carbs...earlier i was reading about the float depth but they were talking about bending the little metal flap on the float (i didnt do that) should i drill out the lead caps and clean it through that way? i dont want to get too much over my head, im very competent, but my professional focus has been cars so far, and the work on bikes have just been personal and family

At this point I would PM Ducatiman and get some info about rebuild kits or prices to have the carbs cleaned, rebuilt, and adjusted.

[ManiacMack]

ill get home eventually today and ill get some pictures like i said, after i get all of this slapped back together ill give it a shot and possibly invite you ghostt to do a butt dyno...lol...i would love to have someone to give me some tips and share the proper procedures on tearing down this carb and rebuilding it

[ducatiman]

Originally Posted by ManiacMack

ive just been doing a parts replacment, i made sure to keep the pieces that came off going right back where they came, i dont know about the float valves, i was never taught about carbs...earlier i was reading about the float depth but they were talking about bending the little metal flap on the float (i didnt do that) should i drill out the lead caps and clean it through that way? i dont want to get too much over my head, im very competent, but my professional focus has been cars so far, and the work on bikes have just been personal and family

Not trying to beat you up or belittle you here, but without compressed air MINIMUM...your results may require multiple attempts and carb pulls.

The phrases "I cleaned my carbs" "I don't have compressed air" "I used spray carb cleaner" "I didn't look at the float system" "I didn't replace any consumables"....all combine and equate to this....you may get lucky, you may not. Even if you do (get lucky) long term reliability is questionable.

You can't compete, squatting in your driveway using a can of carb spray and a toothbrush...versus modern machines in a full pro workshop environment.

Pics before/after, no tricks, yes they are from the same fella's carbs (though EX500) results of use of my machines and EFFORT to get them that way.

Note that the carb "guts" and passageways (though they can't be seen) receive the same treatment and effort.

[Z1R rider]

Originally Posted by ducatiman

Not trying to beat you up or belittle you here, but without compressed air MINIMUM...your results may require multiple attempts and carb pulls.

The phrases "I cleaned my carbs" "I don't have compressed air" "I used spray carb cleaner" "I didn't look at the float system" "I didn't replace any consumables"....all combine and equate to this....you may get lucky, you may not. Even if you do (get lucky) long term reliability is questionable.

You can't compete, squatting in your driveway using a can of carb spray and a toothbrush...versus modern machines in a full pro workshop environment.

Pics before/after, no tricks, yes they are from the same fella's carbs (though EX500) results of use of my machines and EFFORT to get them that way.

Note that the carb "guts" and passageways (though they can't be seen) receive the same treatment and effort.

Boy I wish I could give "helpful post", but I don't have enough posts yet!

[ManiacMack]

Originally Posted by ducatiman

Not trying to beat you up or belittle you here, but without compressed air MINIMUM...your results may require multiple attempts and carb pulls.

The phrases "I cleaned my carbs" "I don't have compressed air" "I used spray carb cleaner" "I didn't look at the float system" "I didn't replace any consumables"....all combine and equate to this....you may get lucky, you may not. Even if you do (get lucky) long term reliability is questionable.

You can't compete, squatting in your driveway using a can of carb spray and a toothbrush...versus modern machines in a full pro workshop environment.

Pics before/after, no tricks, yes they are from the same fella's carbs (though EX500) results of use of my machines and EFFORT to get them that way.

Note that the carb "guts" and passageways (though they can't be seen) receive the same treatment and effort.

your fine dude, i take constructive criticism well, i would rather learn the right way and know its right than learn the wrong was and think its right while looking like a idiot

[Ghostt]

Learning is good, but unless your willing to invest in some machines, like an ultrasonic cleaner, soda blaster, air compressor, etc... You might be fighting a losing battle.

The right tools for the right job, equals results. Ducatiman has already invested the capital in his tools, add to that his vast knowledge and experience, and sending him a set of carburetors makes sense.

Give it go on your own, but at the very least keep him in mind as an alternative solution, his prices are affordable, cheaper than any motorcycle shop I know of.

[ManiacMack]

i have a air compressor, its just not at the place im living right now, the only other tool i would need would be a parts washer or that thing that machine shops have that cook everything off....i dont have pictures today, i didnt get home till 12:30 am....sorry for the delay

[ManiacMack]

could a bad diaphragm cause these symptoms too? how can you tell if one is bad?

[jkv45]

Originally Posted by ManiacMack

could a bad diaphragm cause these symptoms too? how can you tell if one is bad?

Yes - we discussed that back at post #10.

Look them over closely for rips or tears. Hold them up to the light.

[ducatiman]

Originally Posted by ManiacMack

could a bad diaphragm cause these symptoms too? how can you tell if one is bad?

tears, pinholes anywhere

or folds or other malformations along the outer periphery due to misalignment during assembly (pinching, etc)

diaphragm issue could affect your 6-10K issue...but dying at idle separate circuit.

You very well may have multiple issues within your carbs.

And needless to say apply NO harsh chemicals to diaphragm rubbers.

[ManiacMack]

so just make sure that the outside of the diaphragm is sound and basicallygoing to seal? and there are no rips or tears in it, although the center looks strange, i had hit it with some carb cleaner last time i cleaned it but i didnt soak it, im basically trying to figure out if i f'd up this or its salvagable, ill get some pics too

[ManiacMack]

here are some pics of the current diaphragm

[Ghostt]

That's "A" diagram, to be more exact it's the coaster enriching, part #,43028


The other diagrams we are referring to is the slide diaphragms part # 16126.

Also be sure they are fitting properly into the groove. They can sometimes be a PITA to get them properly seated, I use the freezer trick.



My next day off is Thursday and Friday, might be a road trip in my near future.

[ducatiman]

......further convincing evidence that OP needs PRO service.

Lets see what Ghostt rescue trip yields.

Pic...I just finished assembly of these '93 Suzuki Bandit Mikuni's today...full bang restoration, EVERY consumable including throttle shaft seals...tricky job requiring throttle plate removal to split and service. Owner provided Litetek viton seal kits....both A and B.

[Ghostt]

He needs to at least have one of your rebuilding kits on hand, otherwise it's a wasted trip.

[ducatiman]

in stock, ready to go....ball in OP's court.

[ManiacMack]

the boots on the slides are good, ive checkd them every time, i do plan on getting a rebuild kit, i just gotta ok it with my brother