Ninja 250 throttle issue

HerpDerp1919 · June 14th, 2015, 07:14 PM

Just picked up a 1989 Ninja 250 that hasnt ran in about 2 years. Went through the carbs at least three times, it has good spark, getting fuel. If I choke it and get it above 5k itll run fine when I give it throtle, but as soon as it gets below 5k if i give it any throttle it dies. Any suggestions?

Alex · June 14th, 2015, 07:16 PM

Sounds like it needs a 4th time.

HerpDerp1919 · June 14th, 2015, 07:23 PM

Ther third time I checked EVERYTHING. Made sure every single passageway was clear and free flowing. Anything I should look for? any adjustment recommendations? Im new to bikes and have no manual for this one for adjustments

jkv45 · June 14th, 2015, 07:50 PM

This section should give you most of the basics - http://faq.ninja250.org/wiki/Intake

Ghostt · June 14th, 2015, 09:55 PM

Stupid question time,

Describe exactly what you did cleaning the carburetors.

Did you remove the idle mixture screws? Set float heights? How/what did you use to clean them? Remove all jets and holders? Verify the fuel circuits were clear with an air compressor? Etc...

ducatiman · June 15th, 2015, 06:50 AM

a one-time successful carb clean entails some knowledge, correct equipment,
careful attention to detail, prayer...even voodoo sometimes

HerpDerp1919 · June 15th, 2015, 03:58 PM

The first time i cleaned them, I took them entirely apart. Fuel mixture screws, jets, needles and seats. If you could remove it, It came off. Soaked the carburetors in parts cleaner/ carb cleaner overnight along with the jets and needles. re-assembled. No fire due to old plugs.
Second time, complete tear down again, sprayed carb cleaner in everything and checked all passageways are clear with an air compressor and blew into them with my mouth as well. Re-assemble. Still a throttle issue.
Third time, I pulled the jets and needle and seat out. Verified there were no clogs in the jets and the needles werent sticking. Re-assemble. Still issue.
The second and third time I had my grandfather alongside who has cleaned many a carbs in his day and he is stumped as well. Ive looked at diagrams to make sure I have everything plumbed correctly and I do. The only thing I cant seem to find is what those big plunger (vacuum) things do in the carb. Theyre the big black plastic things inside the carb up top. Any ideas are appreciated. Were checking the valves tonight. Hopefully. Sorry for a long post

ducatiman · June 15th, 2015, 05:41 PM

herp-

Double check......a very common assembly error is inserting the needles OVER (and through) the white retainers (the little things with the feet) This is incorrect.

The needle should be inserted first....directly through the slide....the white retainers then get assembled over the needle heads....

Another common error is losing (or forgetting) one or both needle jets which get inserted under the "main jet holder" (aka emulsion tube)
The needle jets should be visible in the venturi as "collars"....the needles stick in them. Easy to see if missing.

Verify this stuff is all present and accounted for....and in correct order!

HerpDerp1919 · June 15th, 2015, 05:52 PM

Could I get some elaboration on the "little white things with feet?"
I'm 99% sure I assembled that correctly. Just curious on the white thing with feet.

Ghostt · June 15th, 2015, 06:17 PM

Little white feet Part # 16007

HerpDerp1919 · June 15th, 2015, 07:01 PM

Okay. I have everything installed correctly. It holds 150 psi in both cylinders. However, if you hold your hand over the left carb it will rev up, if you put your hand over the right carb it dies.

HerpDerp1919 · June 15th, 2015, 08:04 PM

okay, stupid question time. Im digging around for parts for the carbs. I'm looking at the 09-12 carbs and they look pretty much identical. Will the carbs off an 08-12 work on this bike? were thinking its that black plunger thing that is malfunctioning but thats $150 a piece. I found a set of 08-12 carbs for $140.

Ghostt · June 15th, 2015, 08:24 PM

Quote:

Originally Posted by HerpDerp1919

okay, stupid question time. Im digging around for parts for the carbs. I'm looking at the 09-12 carbs and they look pretty much identical. Will the carbs off an 08-12 work on this bike? were thinking its that black plunger thing that is malfunctioning but thats $150 a piece. I found a set of 08-12 carbs for $140.

Contact @ducatiman for your all your carburetor part needs, and yes he has diaphragms.

Check the diaphragm for damage, also make sure it's installed properly, sometimes they can be a PITA, but a little trick is to put them in the freezer overnight, then quickly install them into the carburetors. The rubber will contract and be a bit stiffer, this makes them easier to install.

ducatiman · June 16th, 2015, 04:07 AM

herp-

is it 16126 you are after? Is the diaphragm (rubber) visibly damaged...perforated, ripped, torn, edge pinched?

HerpDerp1919 · June 16th, 2015, 04:12 AM

16126 seems the likely culprit. I have absolutely no idea what's going on with this carb. There is no visible damage to the diaphragm.

ducatiman · June 16th, 2015, 05:39 AM

consider my pm.

jkv45 · June 16th, 2015, 06:53 AM

What did you set the idle mixture screws at?

Did you confirm the o-ring and washer are in the correct position (assy16014)?

Do the slides rise and fall smoothly (engine off) when you lift them up gently through the rear carb opening?

HerpDerp1919 · June 16th, 2015, 07:38 AM

I set the idle mixture screws at 2.5 turns. Yeah, it's all in the correct order.

jkv45 · June 16th, 2015, 07:49 AM

Quote:

Originally Posted by HerpDerp1919

I set the idle mixture screws at 2.5 turns. Yeah, it's all in the correct order.

Good.

How about the slides - moving smoothly?

Ghostt · June 16th, 2015, 07:58 AM

Quote:

Originally Posted by HerpDerp1919

I set the idle mixture screws at 2.5 turns. Yeah, it's all in the correct order.

Personally I set at 3x and then fine tune from there,

Quote:

Your initial setting should be 3 full turns out from the bottom, remember just slightly tighten them, don't go all Conan on them.

Then warm it up, slowly turn 1 side pilot screw in until the rpms drop, then back out till RPM's peak (and no further)* Twist throttle...see how it reacts...tweak to taste.
Repeat on other side... test ride. You're looking for best throttle response and transition from just cracked to 1/4 throttle opening or so.*

Thats a quickie, 10 cent tutorial on setting pilot screws.**

HerpDerp1919 · June 16th, 2015, 04:49 PM

Okay. Went through the carbs again today and my diaphragms are fully functional. I watched them rise and fall with the throttle. When it gets down about 5k or under and you give it throttle it sucks air and dies. Like maybe it's not getting fuel

Ghostt · June 16th, 2015, 05:20 PM

Quote:

Originally Posted by HerpDerp1919

Okay. Went through the carbs again today and my diaphragms are fully functional. I watched them rise and fall with the throttle. When it gets down about 5k or under and you give it throttle it sucks air and dies. Like maybe it's not getting fuel

Okay stupid question time,

Are you doing all your testing without the airbox hooked up? If so that's not helping.

Why? You ask, here's why,

I would highly recommend that you DO NOT REMOVE THE AIR BOX, the carburetors on the bike are CV type and need to box to function properly, buy a K&N that fits the OEM airbox(K&N KA-2508 Kawasaki High Performance Replacement Air Filter by K&N Amazon.com: K&N KA-2508 Kawasaki High Performance Replacement Air Filter: Automotive Amazon.com: K&N KA-2508 Kawasaki High Performance Replacement Air Filter: Automotive ) that's the short version.

Long boring but important answer, CV carbs stands for "constant velocity". The function of the carbs is dependent on having a calm reservoir (airbox) from which to intake air at said constant velocity. Pods draw from the turbulent, unpredictable air swirling past them as you ride, which is anything but constant. Other carbs work fine with pods. CV's = no bueno, save yourself the headaches.

Now onto jetting, first you need to tune the idle mixture screws first, I recommend 3 full turns out from bottom as a good starting point, then fine tune them afterwards. As far as buying a jet kit, I personally don't have one on either my 250, or 500 ninjas. I did got up one size on my main jets, due to they are lean from the factory, and shimmed the main needles with a small washer.

HerpDerp1919 · June 16th, 2015, 05:43 PM

I never got the factory airbox. So I guess I'll get that as well. Just thinking about putting new jets and seat needles in it.

Ghostt · June 16th, 2015, 06:21 PM

Quote:

Originally Posted by HerpDerp1919

I never got the factory airbox. So I guess I'll get that as well. Just thinking about putting new jets and seat needles in it.

Well not having the OEM airbox isn't helping that's for sure. As far as other items, I would replace the float needle valves, and set the float height regardless, along with the idle needle o-rings. These are consumable items.

Have you contacted @ducatiman ?

HerpDerp1919 · June 16th, 2015, 06:32 PM

Yeah. We've been back and forth. I might just send him the carbs instead of firing up the parts cannon. He seems very knowledgeable and will know what to look for

ForceofWill · June 16th, 2015, 06:36 PM

Quote:

Originally Posted by HerpDerp1919

Yeah. We've been back and forth. I might just send him the carbs instead of firing up the parts cannon. He seems very knowledgeable and will know what to look for

Carbs are like vaginas, most of us know the basic functions but no one really knows what the hell is going on in there.

Ghostt · June 16th, 2015, 06:51 PM

Quote:

Originally Posted by HerpDerp1919

Yeah. We've been back and forth. I might just send him the carbs instead of firing up the parts cannon. He seems very knowledgeable and will know what to look for

I've know him for several years now, and I will personally vouch for him. I would trust him with my carburetors, he's got the proper tools, knowledge, and he believes in craftsmanship, and pride in his workmanship.

He's very well known and respected over at EX-500.com, which is where I know him from.

ducatiman · June 19th, 2015, 06:13 PM

^ thank you for above comments, Ghostt (you have PM)

Lotsa work ahead on these, owned by herpderp. A few issues found upon initial teardown.
i'm confident that in the end, we'll have a runner with presentable, decent clean carbs.... inside and out.

ducatiman · June 19th, 2015, 08:25 PM

and later tonight.....done for the most part, some jetting decisions and changes pending. Innards cleaned, cleared, all circuits confirmed clear....

somebody's going to be mighty surprised i think

Ghostt · June 19th, 2015, 10:52 PM

Another excellent job @ducatiman, I love the before and after pictures, better than new.

PM replied.

Ghostt · June 19th, 2015, 11:09 PM

Quote:

Originally Posted by ForceofWill

Carbs are like vaginas, most of us know the basic functions but no one really knows what the hell is going on in there.

Some of us more experienced people do

just takes a lot of time, in my case over 30 years, and yes both

Ask all my EX's, that's probably the only thing they never complained about.

HerpDerp1919 · June 20th, 2015, 05:11 AM

The pictures @ducatiman has sent me just blow me away. I'm amazed at the work he has done already. You are definitely a professional.

ducatiman · June 20th, 2015, 06:11 AM

thanks Tyler, you have PM re jetting decisions. Let me know.

Edit: jetting decisions now made, I'll be wrapping this up today/tonight.

2nd edit: cracked hose under decel valve replaced, final jetting choices installed, fuel levels
set, adjusted, checked via wet testing.

These are DONE.

Here's a peak at the innards after.

xXecuterXx2 · June 24th, 2015, 06:42 AM

Any updates?

HerpDerp1919 · June 24th, 2015, 08:01 AM

Waiting on the carbs to get here yet. Should be here tomorrow.

HerpDerp1919 · June 25th, 2015, 05:36 PM

Well, got em on the bike tonight. Runs great!! But, I now have discovered a bent front rim

so alas, one more thing holding me back from riding

Ghostt · June 25th, 2015, 08:23 PM

Quote:

Originally Posted by HerpDerp1919

Well, got em on the bike tonight. Runs great!! But, I now have discovered a bent front rim

so alas, one more thing holding me back from riding

Man you can't catch a break can you? Well at least those are cheap, don't forget new wheel bearings too while your in the neighborhood.

Also how's the forks, brakes,head bearings, etc.... Just something to think about
So I'm guessing your satisfied with @ducatiman work? Pictures?

June 14th, 2015, 07:14 PM	#1
HerpDerp1919 ninjette.org member Name: Tyler Location: Monticello, MN Join Date: Jun 2015 Motorcycle(s): 1989 Kawasaki Ninja 250 Posts: 20	Ninja 250 throttle issue Just picked up a 1989 Ninja 250 that hasnt ran in about 2 years. Went through the carbs at least three times, it has good spark, getting fuel. If I choke it and get it above 5k itll run fine when I give it throtle, but as soon as it gets below 5k if i give it any throttle it dies. Any suggestions?

June 14th, 2015, 07:16 PM	#2
Alex ninjette.org dude Name: 1 guess :-) Location: SF Bay Area Join Date: Jun 2008 Motorcycle(s): '13 Ninja 300 (white, the fastest color!), '13 R1200RT, '14 CRF250L, '12 TT-R125LE Posts: Too much. Blog Entries: 7	Sounds like it needs a 4th time. __________________________________________________ Montgomery Street Motorcycle Club / cal24.com / crf250l.org / ninjette.org ninjette.org Terms of Service Shopping for motorcycle parts or equipment? Come here first. The friendliest Ninja 250R/300/400 forum on the internet! (especially Unregistered)

June 14th, 2015, 09:55 PM	#5
Ghostt in your machine Name: Scott Location: Summer Shade, Ky. Join Date: Oct 2014 Motorcycle(s): 98 Ninja 250/F12 aka ZX-2R "SERENITY", 91 Ninja 500/A5 aka ZX-5R "Phoenix", 84 Honda GL1200A "SIREN" Posts: A lot. Blog Entries: 25 MOTM - Jun '17, May '16, Mar '15	Stupid question time, Describe exactly what you did cleaning the carburetors. Did you remove the idle mixture screws? Set float heights? How/what did you use to clean them? Remove all jets and holders? Verify the fuel circuits were clear with an air compressor? Etc... __________________________________________________ *violente et ignorantia* ZX-2R BLOG *Twitter and Instagram = Ghostt_Scott* *I'm not here to change your mind, just to inform.*

June 15th, 2015, 06:50 AM	#6
ducatiman ninjette.org certified postwhore Name: Gordon Location: new york Join Date: Sep 2009 Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R Posts: A lot. MOTM - Nov '18, Mar '17	a one-time successful carb clean entails some knowledge, correct equipment, careful attention to detail, prayer...even voodoo sometimes
	1 out of 1 members found this post helpful.

June 15th, 2015, 05:41 PM	#8
ducatiman ninjette.org certified postwhore Name: Gordon Location: new york Join Date: Sep 2009 Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R Posts: A lot. MOTM - Nov '18, Mar '17	herp- Double check......a very common assembly error is inserting the needles OVER (and through) the white retainers (the little things with the feet) This is incorrect. The needle should be inserted first....directly through the slide....the white retainers then get assembled over the needle heads.... Another common error is losing (or forgetting) one or both needle jets which get inserted under the "main jet holder" (aka emulsion tube) The needle jets should be visible in the venturi as "collars"....the needles stick in them. Easy to see if missing. Verify this stuff is all present and accounted for....and in correct order!
	1 out of 1 members found this post helpful.

June 14th, 2015, 07:23 PM	#3
HerpDerp1919 ninjette.org member Name: Tyler Location: Monticello, MN Join Date: Jun 2015 Motorcycle(s): 1989 Kawasaki Ninja 250 Posts: 20	Ther third time I checked EVERYTHING. Made sure every single passageway was clear and free flowing. Anything I should look for? any adjustment recommendations? Im new to bikes and have no manual for this one for adjustments

June 14th, 2015, 07:50 PM	#4
jkv45 Rev Limiter Name: Jay Location: WI Join Date: Jul 2013 Motorcycle(s): '06 SV650n, '00 Derbi GPR, '64 CA77 Dream 305, '70 CL450 Scrambler, numerous dirt bikes Posts: A lot. MOTM - Jun '18, Oct '16	This section should give you most of the basics - http://faq.ninja250.org/wiki/Intake

June 15th, 2015, 03:58 PM	#7
HerpDerp1919 ninjette.org member Name: Tyler Location: Monticello, MN Join Date: Jun 2015 Motorcycle(s): 1989 Kawasaki Ninja 250 Posts: 20	The first time i cleaned them, I took them entirely apart. Fuel mixture screws, jets, needles and seats. If you could remove it, It came off. Soaked the carburetors in parts cleaner/ carb cleaner overnight along with the jets and needles. re-assembled. No fire due to old plugs. Second time, complete tear down again, sprayed carb cleaner in everything and checked all passageways are clear with an air compressor and blew into them with my mouth as well. Re-assemble. Still a throttle issue. Third time, I pulled the jets and needle and seat out. Verified there were no clogs in the jets and the needles werent sticking. Re-assemble. Still issue. The second and third time I had my grandfather alongside who has cleaned many a carbs in his day and he is stumped as well. Ive looked at diagrams to make sure I have everything plumbed correctly and I do. The only thing I cant seem to find is what those big plunger (vacuum) things do in the carb. Theyre the big black plastic things inside the carb up top. Any ideas are appreciated. Were checking the valves tonight. Hopefully. Sorry for a long post

June 15th, 2015, 05:52 PM	#9
HerpDerp1919 ninjette.org member Name: Tyler Location: Monticello, MN Join Date: Jun 2015 Motorcycle(s): 1989 Kawasaki Ninja 250 Posts: 20	Could I get some elaboration on the "little white things with feet?" I'm 99% sure I assembled that correctly. Just curious on the white thing with feet.

June 15th, 2015, 06:17 PM	#10
Ghostt in your machine Name: Scott Location: Summer Shade, Ky. Join Date: Oct 2014 Motorcycle(s): 98 Ninja 250/F12 aka ZX-2R "SERENITY", 91 Ninja 500/A5 aka ZX-5R "Phoenix", 84 Honda GL1200A "SIREN" Posts: A lot. Blog Entries: 25 MOTM - Jun '17, May '16, Mar '15	Little white feet Part # 16007 __________________________________________________ *violente et ignorantia* ZX-2R BLOG *Twitter and Instagram = Ghostt_Scott* *I'm not here to change your mind, just to inform.*

June 15th, 2015, 07:01 PM	#11
HerpDerp1919 ninjette.org member Name: Tyler Location: Monticello, MN Join Date: Jun 2015 Motorcycle(s): 1989 Kawasaki Ninja 250 Posts: 20	Okay. I have everything installed correctly. It holds 150 psi in both cylinders. However, if you hold your hand over the left carb it will rev up, if you put your hand over the right carb it dies.

June 15th, 2015, 08:04 PM	#12
HerpDerp1919 ninjette.org member Name: Tyler Location: Monticello, MN Join Date: Jun 2015 Motorcycle(s): 1989 Kawasaki Ninja 250 Posts: 20	okay, stupid question time. Im digging around for parts for the carbs. I'm looking at the 09-12 carbs and they look pretty much identical. Will the carbs off an 08-12 work on this bike? were thinking its that black plunger thing that is malfunctioning but thats $150 a piece. I found a set of 08-12 carbs for $140.

June 16th, 2015, 04:07 AM	#14
ducatiman ninjette.org certified postwhore Name: Gordon Location: new york Join Date: Sep 2009 Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R Posts: A lot. MOTM - Nov '18, Mar '17	herp- is it 16126 you are after? Is the diaphragm (rubber) visibly damaged...perforated, ripped, torn, edge pinched?

June 16th, 2015, 04:12 AM	#15
HerpDerp1919 ninjette.org member Name: Tyler Location: Monticello, MN Join Date: Jun 2015 Motorcycle(s): 1989 Kawasaki Ninja 250 Posts: 20	16126 seems the likely culprit. I have absolutely no idea what's going on with this carb. There is no visible damage to the diaphragm.

June 16th, 2015, 05:39 AM	#16
ducatiman ninjette.org certified postwhore Name: Gordon Location: new york Join Date: Sep 2009 Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R Posts: A lot. MOTM - Nov '18, Mar '17	consider my pm.

June 16th, 2015, 06:53 AM	#17
jkv45 Rev Limiter Name: Jay Location: WI Join Date: Jul 2013 Motorcycle(s): '06 SV650n, '00 Derbi GPR, '64 CA77 Dream 305, '70 CL450 Scrambler, numerous dirt bikes Posts: A lot. MOTM - Jun '18, Oct '16	What did you set the idle mixture screws at? Did you confirm the o-ring and washer are in the correct position (assy16014)? Do the slides rise and fall smoothly (engine off) when you lift them up gently through the rear carb opening?

June 16th, 2015, 07:38 AM	#18
HerpDerp1919 ninjette.org member Name: Tyler Location: Monticello, MN Join Date: Jun 2015 Motorcycle(s): 1989 Kawasaki Ninja 250 Posts: 20	I set the idle mixture screws at 2.5 turns. Yeah, it's all in the correct order.

June 16th, 2015, 04:49 PM	#21
HerpDerp1919 ninjette.org member Name: Tyler Location: Monticello, MN Join Date: Jun 2015 Motorcycle(s): 1989 Kawasaki Ninja 250 Posts: 20	Okay. Went through the carbs again today and my diaphragms are fully functional. I watched them rise and fall with the throttle. When it gets down about 5k or under and you give it throttle it sucks air and dies. Like maybe it's not getting fuel

June 16th, 2015, 05:43 PM	#23
HerpDerp1919 ninjette.org member Name: Tyler Location: Monticello, MN Join Date: Jun 2015 Motorcycle(s): 1989 Kawasaki Ninja 250 Posts: 20	I never got the factory airbox. So I guess I'll get that as well. Just thinking about putting new jets and seat needles in it.

June 16th, 2015, 06:32 PM	#25
HerpDerp1919 ninjette.org member Name: Tyler Location: Monticello, MN Join Date: Jun 2015 Motorcycle(s): 1989 Kawasaki Ninja 250 Posts: 20	Yeah. We've been back and forth. I might just send him the carbs instead of firing up the parts cannon. He seems very knowledgeable and will know what to look for

June 19th, 2015, 10:52 PM	#30
Ghostt in your machine Name: Scott Location: Summer Shade, Ky. Join Date: Oct 2014 Motorcycle(s): 98 Ninja 250/F12 aka ZX-2R "SERENITY", 91 Ninja 500/A5 aka ZX-5R "Phoenix", 84 Honda GL1200A "SIREN" Posts: A lot. Blog Entries: 25 MOTM - Jun '17, May '16, Mar '15	Another excellent job @ducatiman, I love the before and after pictures, better than new. PM replied. __________________________________________________ *violente et ignorantia* ZX-2R BLOG *Twitter and Instagram = Ghostt_Scott* *I'm not here to change your mind, just to inform.*

June 20th, 2015, 05:11 AM	#32
HerpDerp1919 ninjette.org member Name: Tyler Location: Monticello, MN Join Date: Jun 2015 Motorcycle(s): 1989 Kawasaki Ninja 250 Posts: 20	The pictures @ducatiman has sent me just blow me away. I'm amazed at the work he has done already. You are definitely a professional.

June 24th, 2015, 06:42 AM	#34
xXecuterXx2 ChocolateMilk Addict Name: Maurice Location: McDonough Join Date: Mar 2015 Motorcycle(s): '05 EX-250 "Kallie" 85 KLT 110 ATC "Murdock" Posts: 329	Any updates?

June 24th, 2015, 08:01 AM	#35
HerpDerp1919 ninjette.org member Name: Tyler Location: Monticello, MN Join Date: Jun 2015 Motorcycle(s): 1989 Kawasaki Ninja 250 Posts: 20	Waiting on the carbs to get here yet. Should be here tomorrow.

June 25th, 2015, 05:36 PM	#36
HerpDerp1919 ninjette.org member Name: Tyler Location: Monticello, MN Join Date: Jun 2015 Motorcycle(s): 1989 Kawasaki Ninja 250 Posts: 20	Well, got em on the bike tonight. Runs great!! But, I now have discovered a bent front rim so alas, one more thing holding me back from riding

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