Can't rev with or without choke and backfiring

[Brad92]

Hey everyone,

New here as a member but been repairing my bike here and everything has been going awesome thanks for the great resources.

I have one new problem I can't seem to find an answer to....

So my bike was sitting for years, I cleaned the fuel lines the carbs and changed oil. Everything ran ok just a bit slow so I knew some adjusting was still needed at the clutch cable or carbs.


Out of nowhere though, the other day I'm slowing down and when I go to accelerate again I can't rev past 4k with oor without choke. The bike backfires and pops with each throttle movement.

The only way to get the bike moving is to jolt the throttle from open to close repetitively to get it finally to stick over 6k.

The bike was running fine all things considered before this random event. This random loss of power and back firing was after a rainy day too, so I thought it could be a wet air filter... no luck there.

I tore the bike down again and cleaned the carbs and still it won't rev, can't idle without choke, choke idle can't even pass 4k easily.

I have the battery on a tender and sure it's charged, I changed the spark plugs a day or so before this started happening and I changed oil 2 times since I got the bike to move again after being off for 3 years.

Can my carbs be out of sync? Why would this have happened so abruptly at a light?

[Ghostt]

Carb sync isn't your problem.

Is the gas fresh? Is there water in the gas? When it does it have to try to open the gas cap to see if this might be a vent issue? Vacuum leaks?

I will defer to @ducatiman

[DannoXYZ]

Hi Brad and welcome!

You've got a complex problem on your hands with potentially multiple overlapping issued. First, some questions:

1. What preparations were done to bike in anticipation of 3-yrs of sitting?
2. What did you actually do when you "cleaned the carbs"?

[Brad92]

the bike was kept poorly no cover just in a backyard. to clean the carbs I took them apart, cleaned the jets for hours in. soaked carb dip, then scrubbed the carb bodies good and everything. I actually ended up doing it twice.

[ducatiman]

Originally Posted by Brad92

Hey everyone,
So my bike was sitting for years,
Out of nowhere though, the other day I'm slowing down and when I go to accelerate again I can't rev past 4k with oor without choke. The bike backfires and pops with each throttle movement.

agreed, not a synch issue.

Just *how many* years did it sit outside?
when you performed your carb work, did you visually inspect both diaphragms for rot or excessive dry condition?
Under extreme storage conditions, constant exposure to changing conditions wet, humid, dry... absolutely justifies full carb teardown, inspection and REFURB. ALL consumables need replacement, without hesitation. Float system cleaned, calibrated and tested.

Your immediate, specific problem sounds like a diaphragm issue. Beyond, your carbs need a comprehensive clean and refurb to become reliable again. Just fix the one issue...you'll encounter another given time. How much time? No way to tell....and that spells unreliable where I come from.

[Brad92]

So is this the carbs to blame? How would that have made me suddenly have this issue. The bike didn't run and after cleaning the carbs it was like riding on 70% power. No backfires or need for excessive choke. Then out of nowhere at a red light I can't rev up. I pull throttle it revs down unless you jerk it back and forth really quickly to keep it stable and climbing. It won't rev over 4k and wjen it does I get pops in the exhaust. The bike was fine and was running somewhat acceptable then abruptly did this so while trying to fix it in cleaned the carbs again. Now it still has the same problem but when i can rev up enough to move it has 100% power back. Slow down, or turn off choke bike dies.


Would a video be more helpful

[jkv45]

Chances are debris dislodged and is stuck somewhere in the passages of the carb.

I'd drain the tank and check its condition inside. Also check that the vent tube that comes out the back is open all the way.

Check if there is an inline fuel filter at the carb inlet, and if it's clogged.

After cleaning everything I would add a larger inline filter, but be careful not to create a low spot that will affect fuel flow.

If you didn't remove the idle mixture screws (and caps covering them) you should. The passage need to be clean and there needs to be a spring, washer, and o-ring on each one. The o-rings can get damaged and lodged in the passages and the passages can get partially blocked from sitting.

More info - https://faq.ninja250.org/wiki/Intake

[Brad92]

but how does this happen at a red light? It literally went from a bike that was doing semi alright to BOOM nothing. had to walk it home. heres some videos I took to show what I'm dealing with now

https://youtu.be/xlCkrbaRDn0

https://youtu.be/oIj4Mk45gQg

the last video is the exhaust. I couldn't get it to backfire because it wouldn't let me rev up this time.

Im really lost... because even after letting it sit for years a carb cleaning got it to run. 200 miles later it just stalls out and bogs at a red light.

[Triple Jim]

It can happen. I was at the track with my DT100 and took a break from riding. When I started the bike a few minutes later, it had symptoms similar to yours... it wouldn't rev or make significant power. I took the bowl off the carb and found a chunk of dirt stuck in the main jet.

That's when I decided to stop using sintered metal fuel filters and switched to pleated paper ones.

[Brad92]

after it happened I took the carbs apart and cleaned it aggressively and it still won't work correctly? did I need to do anything besides clean them (by hand not just additives)

[taz]

refer to this thread for a deep clean on the carbs


https://www.ninjette.org/forums/show...=carb+cleaning

[ducatiman]

ty, Taz. Difficult to compete with the aggressive cleaning ability of modern machines.

https://youtu.be/nEduht9V0nI uploaded vid to youtube, techie I am.
(thats my old ultrasonic machine...got a big, powerful sumabich now)


Between sodablast, ultrasonic, heavy compressed air ...the "hidden, invisible passageways" are successfully dealt with. Simply spraying them with carb cleaner may or may not clear them..depending on severity. Some get lucky...but I like to use an elephant gun to shoot an ant...assuring the passageways are clear.

[Brad92]

I still can't believe its just the carb at this point. IT ran fine then abruptly died. then I cleaned the carbs again and theres no luck. I CLEANED them excessively as best I can for a home job.


All I can remember was I was riding fine like 40mph, someone made a left hand turn so I dropped a gear and slowed down, then I dropped all the way to first at the red light about 100ft later. Green light hits and I can't move at all bike dies under any throttle

[ducatiman]

have you since examined the diaphragms?

can you view my vid, btw?

[Brad92]

Ducatiman , I live in NYC so I just messaged you. Im interested in your service. How long does the turn around take?

[ducatiman]

24-48 hour, all parts in stock, i'll view your pm now

[DannoXYZ]

Your carbs may also be victims of tank issues. Here's some commonly used techniques for long-term storage:

1. 6-months winter storage. Fill tank up to top with gas and fuel-stabilizer. Store in location with minimal variations in humidity and temperature

2. 6-months or more. Tank is completely drained. Coated on inside with engine-oil (or completely filled). Carbs drained of gas, dried and vacuum-bagged. Store in location with minimal variations in humidity and temperature.

What happens with letting bike sit is moisture accumulates in the tank and rusts areas that's not filled with gas or oil. That rust took some time and vibration to break off and work it's way down into your carbs and clogged them.

While ducatiman is working on your carbs, you'll want to get a USB borescope and look around in your tank. Especially in the corners and seams. The rust needs to be physically scrubbed off. The surface then chemically treated and then sealant used to cover bare metal.

[Brad92]

how much for a new tank or to have that done professionally? I feel by the time I get the camera to inspect it the sealant and man hours I could have just paid close to the same for a pro job.

[ducatiman]

Hate to "plie on" but the petcock needs to be checked as well. While there, the tank cap vent diaphragms removed.

Consider a POR-15 treatment/coating for the tank. I can do...you need a hose, plenty of water and drainage. Its wet/messy but very effective. But 96 hour cure time on the final stage. It'll never rust again. EVER.

Can do all of above...I'll PM u again.

[Brad92]

pm me asap, Ill be out by you today so if you are available I can drop everything off. Lets talk details in a PM

[jkv45]

I'm still betting on the carb, but you can remove the air filter and give it a quick shot of Starter Fluid in the airbox to confirm it's a fueling issue. You may need to crack the throttle slightly as you are cranking, but you should get at least a sputter of some kind.

Or pull the plugs and test for a spark.

EDIT: Your video sounds like a carb/fueling problem to me.

[Triple Jim]

I prefer to clean thanks as well as I can, including using small gravel and shaking it around with laqcuer thinner if necessary. If the metal is not severly rusted, I then use it without sealer, and always put a pleated paper fuel filter in the line.

[taz]

Originally Posted by ducatiman

ty, Taz. Difficult to compete with the aggressive cleaning ability of modern machines.

https://youtu.be/nEduht9V0nI uploaded vid to youtube, techie I am.
(thats my old ultrasonic machine...got a big, powerful sumabich now)


Between sodablast, ultrasonic, heavy compressed air ...the "hidden, invisible passageways" are successfully dealt with. Simply spraying them with carb cleaner may or may not clear them..depending on severity. Some get lucky...but I like to use an elephant gun to shoot an ant...assuring the passageways are clear.

video is private, so no go on the view.

[ducatiman]

i've set vid to public, should be viewable , no?

Brad and I have spoke via phone...he's to be here later with carbs, tank, petcock...we'll give a looksee.

[Brad92]

Thanks everyone for the help. I appreciate everything offered to me especially on my first day on this site! looks like I lucked out and get to avoid the spealership

[Ghostt]

Originally Posted by ducatiman

i've set vid to public, should be viewable , no?

Brad and I have spoke via phone...he's to be here later with carbs, tank, petcock...we'll give a looksee.

it will be interesting to hear your findings about his issues.

[ducatiman]

16126VALVE,VACUUM
16126-1198 16126-1200
$160.82
$144.74



Thats the current RonAyers EACH price for new diaphragm/slide assemblies for 08'-12' 250's.

Holy schmoly.

[DannoXYZ]

Can you replace just diaphragm?

[ducatiman]

no separate part number for rubber only...slide/rubber sold as an assembly by Kawasaki

[DannoXYZ]

Interesting. Must be breakers separating parts.
EDIT: removed incompatible parts to avoid confusion.

[ducatiman]

the 2nd listing @ 67mm is incorrect....not for 250

the first listing appears to be aftermarket...sure would like a confirming dimension on that

Also, the ability of inner circumference to be radically stretched for removal and installation (without being torn) may be questionable.
I'll take a look at a damaged slide to see if rubber removal is possible at all via stretching. The top, hard plastic retainer, to my knowledge, isn't serviceable at all...removal would require damage.

[ducatiman]

I got some very good news from OP Brad....but I'll let him describe within his own thread.

Awaiting his feedback here before awarding him with a "yeah baby!" from Austin Powers....but you know its comin'.

[Brad92]

I cant thank Gordon enough for all the help with my bike!

Not only did he help get me running again he was the most honest person I've ever dealt with. He's extremely knowledgeable and friendly and genuinely wants to surpass your expectations of quality service.

Thank you Gordon for the immediate assistance. It turned out the Carb diaphragm was ripped (just like he mentioned on the post here before I showed up) the moment he found that he called me and offered to sell me a carb kit he already refurbished. I through those carbs in and boom new bike! I haven't been this happy with this bike since 2012! Seriously thank you Gordon and thanks to the community for pointing me in the right direction.

[Z1R rider]

Don't ya just love it when a plan comes together?

[Triple Jim]

I'm very interested hearing about the aftermarket diaphragms if you do investigate them, Gordon.

[ducatiman]

Now that Brad has checked in...if I may, i'll better explain my findings. Not just 1 but 2 torn diaphragm rubbers. It was likely running intermittently on 1 cylinder (?) relying on one (not so bad) torn rubber... just barely holding its own....then POP....the hole became a tear, rendering the slide inop....thus explaining his immediate, dramatic breakdown. Yes, it was the carbs.

A set of refurbs from my stock were affordable and quick....just a quick review and setup, swap his hoses in....a handoff and done.
A bench test...petcock ok. Inside of tank clean and clear (miracle?)

Timeline...2AM yesterday...Brad joins forum, posts problem
noon yesterday...decides to bring carbs to me
6PM yesterday leaves with a set of REFURBS from my stock
9PM yesterday...texts me bike is running great

Can't do any better or quicker. Glad Brad is up and running.
For that Austin yells and screams ......

[DannoXYZ]

Awesome work Gordon!!!

[ducatiman]

ty, JacR...thats what its all about, I'm here to personally serve, support and help fellow enthusiasts..meanwhile building a small, specialized, efficient little carb enterprise.

[DirtyPelican]

Thats great to hear, had I not tried my hand at cleaning my carbs, you would be my go to guy for sure. Let me not jinx myself, you might end up hearing from me yet, once I get the bike on the road and under load.

[Brad92]

Pelican, I cleaned mine myself too at first (probably how the diaphragm ripped. I thought I got everything out and did a decent job, but Gordon really knows his stuff and pointed out everything I did wrong so I can learn from my own mistakes. Theres no beating the machinery he has access to to clean your carbs. I just used regular old carb cleaner and a tooth brush.

Gordon goes in with a multi stage cleaning with a soda blaster and a ultrasonic cleaner.

There is not one shop in all of NYC and Long Island that even OFFERS THAT!!! Every shop I went to or called told me double the price Gordon offered and gave me similar answers when I asked how they would be cleaned and inspected.

Every shop said "yea we will take it apart and soak it for 24hours in carb cleaner" or my favorite " we will let it sit in pin-sol for a night"

Not one Service location even knew what soda blasting or ultra sonic cleaning was. If it wasn't of this forums great resources I would never have known either or found Gordon!

He's my go to guy for everything from here on out. Super professional, friendly and all around great mechanic what more can I ask for