carb problems 1996 ninja 250

mr.jake · January 5th, 2011, 01:29 PM

hi everyone, I’m assuming I have a carb problem with my bike. if I adjust the idle screw below 4,000 rpm my bike cuts off. also after starting my bike and giving it time to warm up when I go to take off in first gear the moment I start to release the clutch the bike almost cuts off. but when I pull the clutch lever in it idles fine. if I do this 5 or 6 times while revving the engine to 10,000 rpm it will take off... why is this? Any tips on what I should do? I have been using sea foam in my gas and it is still doing this. should I take off my carbs and clean them? or is it a bigger problem? should I change my air filter?

FrugalNinja250 · January 6th, 2011, 07:04 AM

You'll need to fully dismantle and clean the carbs, especially the air bleeds and idle jet passages. To do this really well you need compressed air and a good spray cleaner. I recommend Brakleen (red can,not green can) brake cleaner, it does a great job dissolving carb fuel deposits and will not leave any residue. For compressed air you can use a couple cans of the computer cleaner stuff, but I recommend getting a compressor if you can afford one. Really nice ones can be had for a hundred bucks nowadays at Harbor Freight.

Seafoam is ok for preventative maintenance, but it's not nearly strong enough to clean up old deposits. Anything strong enough to do that would destroy the seals in your petcock and carbs.

TonyKZ1 · January 6th, 2011, 07:50 AM

Yep, what FrugalNinja250 said. You've got carbs that are in need of a good cleaning.
Tony

SV_Hadder · January 6th, 2011, 12:33 PM

Yup, sounds like clogged pilot jets.

mr.jake · January 7th, 2011, 04:51 PM

thank you guys. any vids or instructionals online that i should watch/read? i have a basic idea about how to do it but im kinda nervous about it. thanks

kkim · January 7th, 2011, 07:18 PM

http://faq.ninja250.org/wiki/How_do_...n_the_carbs%3F

mr.jake · January 7th, 2011, 09:08 PM

thanks for the link. is it possible that a dirty carb could be affecting my top speed? my ninja tops out at around 80. i only weigh 185.

kkim · January 7th, 2011, 09:34 PM

depending on how dirty the carb is, the answer could be "yes". If the main jets are clogged up, as we think the pilot jets are, then yes, top speed will be affected.

if the carbs are dirty when you disassemble them, consider removing the fuel tank and emptying it out by dumping the contents out through the fill hole. Slosh some clean gas in there a couple of times and dump that out. refill with nice clean fuel.

also, there is a small inline fuel filter right where the fuel line enters the carbs that you might want to check for additional debris.

fjyang · January 21st, 2011, 09:28 AM

If you're going to take out your carb and clean, I suggest you replace the pilot jet with a bigger size from Sigma Racing. Here is the bay link

http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWAX%3AIT

I swap out my pilot jets and it cures 90% of my cold or hard to start problems. I don't need to be on the choke for 10+ min. to idle normally and its easier to maintain idle with with mods. Besides shiming your needles or a jet kit, this is the second best carb mod you can do to your 250 IMO.

Jinx250 · January 21st, 2011, 04:01 PM

Or just clean the carbs and set them up properly (=free).

mr.jake · February 14th, 2011, 07:05 PM

after throughly cleaning my carbs my ninja is running extremely sluggish. . before i cleaned my carbs it was much faster but had to be kept ideling at 4-5000 rpm or it would cut off. also i had to let it warm up with the coke on for almost 10minutes every time. it idels consitantly at 2500 rpm and starts much easyer not. but it is still slower than a minivan now...

kkim · February 14th, 2011, 07:15 PM

it's slower now even after the motor spins up past 5k?

what did you do when you cleaned the carbs??? any jetting changes?

mr.jake · February 14th, 2011, 07:29 PM

no jetting. cleaned underneath the carbs where the bowls are. took out the main jets and pilot jets and cleaned them. removed one of the top covers of the carbs where the black rubber thing is (not sure the propper name). i may have pinched the black rubber thing?? would that be the cause? could it have been so dirty that it was like having smaller jets? also it seems to have more low-end power. idk what is going on

kkim · February 14th, 2011, 07:41 PM

dunno... maybe you're so used to the bike idling at 4-5k that now when it idles at a lower rpm (BTW, idle should be set to around 1500), it just seems slower until the bike gets to 5k? that's why I asked it the bike is slower even above 5k?

mr.jake · February 14th, 2011, 08:09 PM

same speed at 5k but at 9-13 its veeerrry slow.

kkim · February 14th, 2011, 08:27 PM

check the carb diaphragms (the black rubber things on the inside tops of the carbs). If they get damaged (ripped or pinched) it can affect the rate at which the slides rise and fall in the carbs, which in turn affects the midrange power in the bike.

DaBlue1 · February 15th, 2011, 07:58 AM

Do you have all your vacuum lines right and the carb boots on right and tight?
How old is your bike and how many miles do you have on it. Have you done a compression test?

mr.jake · February 15th, 2011, 08:54 AM

im not sure what a compression test is so i havent done one. my bike is 94. I didn’t remove any vacuum hoses.

January 5th, 2011, 01:29 PM	#1
mr.jake ninjette.org member Name: jacob Location: gaston county n.c. Join Date: Dec 2010 Motorcycle(s): 1996 ninja 250 Posts: 28	carb problems 1996 ninja 250 hi everyone, I’m assuming I have a carb problem with my bike. if I adjust the idle screw below 4,000 rpm my bike cuts off. also after starting my bike and giving it time to warm up when I go to take off in first gear the moment I start to release the clutch the bike almost cuts off. but when I pull the clutch lever in it idles fine. if I do this 5 or 6 times while revving the engine to 10,000 rpm it will take off... why is this? Any tips on what I should do? I have been using sea foam in my gas and it is still doing this. should I take off my carbs and clean them? or is it a bigger problem? should I change my air filter? __________________________________________________ those who think they can and those who think they cannot are usually right.

January 6th, 2011, 07:50 AM	#3
TonyKZ1 ninjette.org member Name: Anthony Location: Marble Hill, MO Join Date: Dec 2008 Motorcycle(s): 1975 Kawasaki KZ400D (Sold), 1989 Kawasaki Ninja 250 (sold), 1997 Yamaha XJ600s Seca II Posts: 231	Yep, what FrugalNinja250 said. You've got carbs that are in need of a good cleaning. Tony __________________________________________________ 1997 Yamaha Seca II - mostly stock, Racetech upgraded forks, FZ6R rear shock, Oxford Heated Grips, Barkbusters Blizzard Handguards, a Scottoiler vSystem chain oiler. My Mileage Tracker Page.

January 6th, 2011, 12:33 PM	#4
SV_Hadder ninjette.org member Name: Zach Location: Raleigh, NC Join Date: Sep 2010 Motorcycle(s): 2001 Ninja 250 Posts: 94	Yup, sounds like clogged pilot jets. __________________________________________________ "Nicole" - Pirelli Diablo's front and rear, Two Brother's Exhaust, Apex Custom SS lines , 15 T, UNI Air filter, Fiamm El Grande horns, EX500 fork springs, EX250J rear shock, Fender eliminator.

January 7th, 2011, 04:51 PM	#5
mr.jake ninjette.org member Name: jacob Location: gaston county n.c. Join Date: Dec 2010 Motorcycle(s): 1996 ninja 250 Posts: 28	thank you guys. any vids or instructionals online that i should watch/read? i have a basic idea about how to do it but im kinda nervous about it. thanks __________________________________________________ those who think they can and those who think they cannot are usually right.

January 7th, 2011, 09:08 PM	#7
mr.jake ninjette.org member Name: jacob Location: gaston county n.c. Join Date: Dec 2010 Motorcycle(s): 1996 ninja 250 Posts: 28	thanks for the link. is it possible that a dirty carb could be affecting my top speed? my ninja tops out at around 80. i only weigh 185. __________________________________________________ those who think they can and those who think they cannot are usually right.

January 6th, 2011, 07:04 AM	#2
FrugalNinja250 ninjette.org certified postwhore Name: Frugal Location: Dallas/Fort Worth (DFW) Join Date: Mar 2010 Motorcycle(s): Several Posts: A lot.	You'll need to fully dismantle and clean the carbs, especially the air bleeds and idle jet passages. To do this really well you need compressed air and a good spray cleaner. I recommend Brakleen (red can,not green can) brake cleaner, it does a great job dissolving carb fuel deposits and will not leave any residue. For compressed air you can use a couple cans of the computer cleaner stuff, but I recommend getting a compressor if you can afford one. Really nice ones can be had for a hundred bucks nowadays at Harbor Freight. Seafoam is ok for preventative maintenance, but it's not nearly strong enough to clean up old deposits. Anything strong enough to do that would destroy the seals in your petcock and carbs.

January 7th, 2011, 07:18 PM	#6
kkim Join Date: Nov 2008 Posts: Too much.	http://faq.ninja250.org/wiki/How_do_...n_the_carbs%3F

January 7th, 2011, 09:34 PM	#8
kkim Join Date: Nov 2008 Posts: Too much.	depending on how dirty the carb is, the answer could be "yes". If the main jets are clogged up, as we think the pilot jets are, then yes, top speed will be affected. if the carbs are dirty when you disassemble them, consider removing the fuel tank and emptying it out by dumping the contents out through the fill hole. Slosh some clean gas in there a couple of times and dump that out. refill with nice clean fuel. also, there is a small inline fuel filter right where the fuel line enters the carbs that you might want to check for additional debris.

January 21st, 2011, 09:28 AM	#9
fjyang ninjette.org member Name: Frank Location: Pasadena Join Date: Mar 2009 Motorcycle(s): 87 Ninja 250, 90 Ninja ZX750R, GPZ 900r, 02 Moto Guzzi LeMans, 95 Triumph Speed Triple Posts: 121	If you're going to take out your carb and clean, I suggest you replace the pilot jet with a bigger size from Sigma Racing. Here is the bay link http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWAX%3AIT I swap out my pilot jets and it cures 90% of my cold or hard to start problems. I don't need to be on the choke for 10+ min. to idle normally and its easier to maintain idle with with mods. Besides shiming your needles or a jet kit, this is the second best carb mod you can do to your 250 IMO.

January 21st, 2011, 04:01 PM	#10
Jinx250 Smoker Name: Bob Location: SoCal Join Date: Dec 2010 Motorcycle(s): Guess.... Posts: 556	Or just clean the carbs and set them up properly (=free).

February 14th, 2011, 07:05 PM	#11
mr.jake ninjette.org member Name: jacob Location: gaston county n.c. Join Date: Dec 2010 Motorcycle(s): 1996 ninja 250 Posts: 28	after throughly cleaning my carbs my ninja is running extremely sluggish. . before i cleaned my carbs it was much faster but had to be kept ideling at 4-5000 rpm or it would cut off. also i had to let it warm up with the coke on for almost 10minutes every time. it idels consitantly at 2500 rpm and starts much easyer not. but it is still slower than a minivan now... __________________________________________________ those who think they can and those who think they cannot are usually right.

February 14th, 2011, 07:15 PM	#12
kkim Join Date: Nov 2008 Posts: Too much.	it's slower now even after the motor spins up past 5k? what did you do when you cleaned the carbs??? any jetting changes?

February 14th, 2011, 07:29 PM	#13
mr.jake ninjette.org member Name: jacob Location: gaston county n.c. Join Date: Dec 2010 Motorcycle(s): 1996 ninja 250 Posts: 28	no jetting. cleaned underneath the carbs where the bowls are. took out the main jets and pilot jets and cleaned them. removed one of the top covers of the carbs where the black rubber thing is (not sure the propper name). i may have pinched the black rubber thing?? would that be the cause? could it have been so dirty that it was like having smaller jets? also it seems to have more low-end power. idk what is going on __________________________________________________ those who think they can and those who think they cannot are usually right.

February 14th, 2011, 07:41 PM	#14
kkim Join Date: Nov 2008 Posts: Too much.	dunno... maybe you're so used to the bike idling at 4-5k that now when it idles at a lower rpm (BTW, idle should be set to around 1500), it just seems slower until the bike gets to 5k? that's why I asked it the bike is slower even above 5k?

February 14th, 2011, 08:09 PM	#15
mr.jake ninjette.org member Name: jacob Location: gaston county n.c. Join Date: Dec 2010 Motorcycle(s): 1996 ninja 250 Posts: 28	same speed at 5k but at 9-13 its veeerrry slow. __________________________________________________ those who think they can and those who think they cannot are usually right.

February 14th, 2011, 08:27 PM	#16
kkim Join Date: Nov 2008 Posts: Too much.	check the carb diaphragms (the black rubber things on the inside tops of the carbs). If they get damaged (ripped or pinched) it can affect the rate at which the slides rise and fall in the carbs, which in turn affects the midrange power in the bike.

February 15th, 2011, 07:58 AM	#17
DaBlue1 Long Time Rider Name: Blue Location: Charlotte, NC Join Date: Sep 2010 Motorcycle(s): 2009 Kawasaki Ninja 250R Posts: A lot.	Do you have all your vacuum lines right and the carb boots on right and tight? How old is your bike and how many miles do you have on it. Have you done a compression test?

February 15th, 2011, 08:54 AM	#18
mr.jake ninjette.org member Name: jacob Location: gaston county n.c. Join Date: Dec 2010 Motorcycle(s): 1996 ninja 250 Posts: 28	im not sure what a compression test is so i havent done one. my bike is 94. I didn’t remove any vacuum hoses. __________________________________________________ those who think they can and those who think they cannot are usually right.

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