ninjette.org

Go Back   ninjette.org > 1986 - 2007 Ninja 250R > 1986 - 2007 Ninja 250R Tech Talk

Reply
 
Thread Tools
Old November 30th, 2019, 05:54 PM   #1
Detrailers
ninjette.org member
 
Name: Jeff
Location: Corinth tx
Join Date: Jul 2019

Motorcycle(s): '85 750 Turbo E2 - '86 600 Ninja - '82 FT 500 Ascot

Posts: 10
Carb issue

Have a 2007 Ninja 250r that I rescued. Got everything back together, fully cleaned carbs and gas tank. Has a new aftermarket vacuum operated fuel petcock, new plugs and air filter too. I've got one last issue that is driving me mad. I can't get it to idle right. If I twist the idle thumbscrew enough to get it to idle, then the revs dont come down when you blip the throttle. If I turn it down to where the revs come down quicker then it dies and when it does, really hard to restart. Any ideas??
I'm wondering if I pull the caps off the idle screws and bring them out a bit if that will help.
Detrailers is offline   Reply With Quote




Old November 30th, 2019, 06:25 PM   #2
ducatiman
ninjette.org certified postwhore
 
ducatiman's Avatar
 
Name: Gordon
Location: new york
Join Date: Sep 2009

Motorcycle(s): '95 DUCATI 900SS/SP '98 HONDA VFR800 '07 DUCATI SS800 '19 HONDA CBR650R

Posts: A lot.
MOTM - Nov '18, Mar '17
i'd suggest a synch with an accurate, pro manometer, followed by setting each pilot screw to its "sweet spot"....highest RPM with best response done with bike fully warmed.
__________________________________________________
Gordon
Custom Carb Service

www.customcarbservices.com
ducatiman is online now   Reply With Quote


Old November 30th, 2019, 08:54 PM   #3
Detrailers
ninjette.org member
 
Name: Jeff
Location: Corinth tx
Join Date: Jul 2019

Motorcycle(s): '85 750 Turbo E2 - '86 600 Ninja - '82 FT 500 Ascot

Posts: 10
I just thought of something else too, if the idle screws are still factory sealed, could they still be clogged because I was unable to remove and clean them and this causing idle issues? I soaked both bodies in carb dip but maybe the needle gummed up
Detrailers is offline   Reply With Quote


Old November 30th, 2019, 10:04 PM   #4
BoBO
ninjette.org guru
 
BoBO's Avatar
 
Name: Genesis
Location: Rohnert Park CA
Join Date: Jan 2014

Motorcycle(s): 08 ninja 250R

Posts: 376
If the idle is hanging the carb is out of sync. I would sync first and re adjusting the pilot screw just like Ducatiman mentioned.

If the carb is already out you might want to install a Dynojet kit for an improved idle and less hesitation. It's different for every Ninja, but my 250 would hesitate on idle and at 6500rpm before I did a re-jet. Now it's just smooth all the way.
__________________________________________________
08 Ninja 250 track-prepared
04 BMW Z4 2.5 M Package
01 R170 AMG Sport Package
BoBO is offline   Reply With Quote


Old November 30th, 2019, 10:36 PM   #5
Detrailers
ninjette.org member
 
Name: Jeff
Location: Corinth tx
Join Date: Jul 2019

Motorcycle(s): '85 750 Turbo E2 - '86 600 Ninja - '82 FT 500 Ascot

Posts: 10
Well I know what I'll be doing tommorow.. thx everyone
Detrailers is offline   Reply With Quote


Old November 30th, 2019, 11:58 PM   #6
DannoXYZ
ninjette.org certified postwhore
 
Name: AKA JacRyann
Location: SF East Bay
Join Date: Dec 2011

Motorcycle(s): CB125T, Ninja250R racer, Ninja250R street bike, EX250F#1, EX250F#2, EX250E, VF500F, CBR600RR

Posts: A lot.
MOTY - 2018, MOTM - Nov '17
Jet kit not needed unless you’ve got bigger pistons, wild cams and/or full exhaust upgrade. Stock engine and carbs can be tuned optimally by adjusting pilot screws.
DannoXYZ is offline   Reply With Quote


Old December 1st, 2019, 07:38 AM   #7
ducatiman
ninjette.org certified postwhore
 
ducatiman's Avatar
 
Name: Gordon
Location: new york
Join Date: Sep 2009

Motorcycle(s): '95 DUCATI 900SS/SP '98 HONDA VFR800 '07 DUCATI SS800 '19 HONDA CBR650R

Posts: A lot.
MOTM - Nov '18, Mar '17
Quote:
Originally Posted by Detrailers View Post
I just thought of something else too, if the idle screws are still factory sealed, could they still be clogged because I was unable to remove and clean them and this causing idle issues? I soaked both bodies in carb dip but maybe the needle gummed up
If pilot screws remain factory sealed, the pilot circuits were never *truly* cleaned within your efforts.

As an '07 is how old now? I'd suggest to have new pilot orings *on hand* before attacking this. Upon disassembly, they are usually found flattened.

My synch and adjustment suggestions still stand as well, just basic tuning reaction to your reported idle fluctuations
__________________________________________________
Gordon
Custom Carb Service

www.customcarbservices.com
ducatiman is online now   Reply With Quote


Old December 1st, 2019, 09:38 PM   #8
Detrailers
ninjette.org member
 
Name: Jeff
Location: Corinth tx
Join Date: Jul 2019

Motorcycle(s): '85 750 Turbo E2 - '86 600 Ninja - '82 FT 500 Ascot

Posts: 10
Thx for all the input. I drilled out the caps today and adjusted the idle screws after thoroughly cleaning them. I also discovered what I think the culprit is, one cylinders float needle was leaking slightly, so I think what was happening is it would start and idle ok, and then fuel would slowly flood the one side which is what would kill the idle and then be tough to restart..

Since I'm there I'm going one step up to 108 mains and one shim under the needle. Everywhere I read said these bikes were lean and one step up on the needle and MJ helps them quite a bit. Please stop me if this is wrong but every liquid cooled Kawi I've ever worked on has been lean stock.
Detrailers is offline   Reply With Quote


Old December 2nd, 2019, 12:20 AM   #9
BoBO
ninjette.org guru
 
BoBO's Avatar
 
Name: Genesis
Location: Rohnert Park CA
Join Date: Jan 2014

Motorcycle(s): 08 ninja 250R

Posts: 376
Quote:
Originally Posted by Detrailers View Post
Thx for all the input. I drilled out the caps today and adjusted the idle screws after thoroughly cleaning them. I also discovered what I think the culprit is, one cylinders float needle was leaking slightly, so I think what was happening is it would start and idle ok, and then fuel would slowly flood the one side which is what would kill the idle and then be tough to restart..

Since I'm there I'm going one step up to 108 mains and one shim under the needle. Everywhere I read said these bikes were lean and one step up on the needle and MJ helps them quite a bit. Please stop me if this is wrong but every liquid cooled Kawi I've ever worked on has been lean stock.
They usually come lean no doubt. That's why I mentioned every Ninja 250 is different. I though my bike was stock until I did a tune up and found out I had K&N filter with no snorkle pipe and drilled airbox. I went with a jet kit followed the recommended setup, saved a bunch of time on tuning, and never looked back. It ran even better when I replaced the air box and added a slipon w baffle using the same dynojet stage 2 setup.

Shimming the needle should take the idle hesitation, but it doesn't always work. Whats been done to your bike? There's a lot of factors to consider. For example, 108 main jets might not work on a stock bike due to running rich, but it might on full exhaust and high flow filter. Carb tuning takes time, on a fully stock bike maybe just play with the idle mixture. I would also check for vacuum leaks that would definitely affect idle problems. Ive had many vacuum leaks on my bike throughout the years.

Also, are the valves in spec before tuning? I did it on my 08 before and if I remember it was shim under bucket, but your 07 should be easier to work on.
__________________________________________________
08 Ninja 250 track-prepared
04 BMW Z4 2.5 M Package
01 R170 AMG Sport Package
BoBO is offline   Reply With Quote


Old December 2nd, 2019, 11:18 PM   #10
Detrailers
ninjette.org member
 
Name: Jeff
Location: Corinth tx
Join Date: Jul 2019

Motorcycle(s): '85 750 Turbo E2 - '86 600 Ninja - '82 FT 500 Ascot

Posts: 10
FIXED! So today I replaced the leaky float needle, put everything back together and it runs great. This along with cleaning and backing out the mix screws, and synching the carbs and it starts and runs smoooooth. Didnt do the 108 mains because the general consensus is it doesn't need it, but I think putting a shim under the needle helped, midrange feels much better.
Detrailers is offline   Reply With Quote


1 out of 1 members found this post helpful.
Old December 3rd, 2019, 07:41 AM   #11
Triple Jim
Guy Who Enjoys Riding
 
Triple Jim's Avatar
 
Name: Jim
Location: North Central North Carolina
Join Date: Jul 2016

Motorcycle(s): Ninja 250

Posts: A lot.
MOTM - Oct '18, Aug '17, Aug '16
Quote:
Originally Posted by Detrailers View Post
...but I think putting a shim under the needle helped, midrange feels much better.
Every case is different, but... I had a shim under each needle and it helped a stumbly midrange that my '05 had. I had it that way for a couple years. Then I had Ducatiman return my carbs to like-new condition and leave out the shims. The engine has never run this well since I bought the bike.
Triple Jim is online now   Reply With Quote


Old December 3rd, 2019, 12:39 PM   #12
DannoXYZ
ninjette.org certified postwhore
 
Name: AKA JacRyann
Location: SF East Bay
Join Date: Dec 2011

Motorcycle(s): CB125T, Ninja250R racer, Ninja250R street bike, EX250F#1, EX250F#2, EX250E, VF500F, CBR600RR

Posts: A lot.
MOTY - 2018, MOTM - Nov '17
Quote:
Originally Posted by Detrailers View Post
FIXED! So today I replaced the leaky float needle, put everything back together and it runs great. This along with cleaning and backing out the mix screws, and synching the carbs and it starts and runs smoooooth. Didnt do the 108 mains because the general consensus is it doesn't need it, but I think putting a shim under the needle helped, midrange feels much better.
Good job! Yeah, going to bigger main jets is hail-mary attempt after not being able to properly clean carbs. Which is what most people do and it "works", so problem was factory jets were too small right?

Well, bike ran fine when brand-new leaving showroom floor, with factory-fresh clean carbs. So there's no reason other than clogged carbs that would cause them to not run like factory-fresh bike (assuming valve-adjustment is correct). Main-jets don't affect idle and off-idle behavior much anyway. Most of that idle and off-idle behavior is adjusted by pilot-screws. So after thorough cleaning back to factory-fresh condition (not possible without ultrasonic and micro soda-blasting), you'll just need to ensure carbs are synced and adjust pilot-screws for "best idle" behavior.
DannoXYZ is offline   Reply With Quote


Reply




Similar Threads
Thread Thread Starter Forum Replies Last Post
Another carb issue malignity 2008 - 2012 Ninja 250R Tech Talk 5 April 1st, 2017 06:03 PM
Yet another Carb issue Foxrider64 2008 - 2012 Ninja 250R Tech Talk 7 October 2nd, 2013 09:38 AM
Strange Carb issue n4mwd 1986 - 2007 Ninja 250R Tech Talk 42 August 26th, 2013 06:05 AM
Carb issue zach 2008 - 2012 Ninja 250R Tech Talk 4 May 24th, 2013 10:54 AM
carb issue. justin_ninja 1986 - 2007 Ninja 250R Tech Talk 8 January 19th, 2013 07:16 PM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


Motorcycle Safety Foundation

All times are GMT -7. The time now is 03:10 PM.


remote server monitor
Powered by vBulletin®
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
User Alert System provided by Advanced User Tagging (Lite) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Except where otherwise noted, all site contents are Copyright 2019 ninjette.org, All rights reserved.