ninjette.org

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

Reply
 
Thread Tools
Old September 13th, 2020, 02:47 PM   #1
crimsondragon
ninjette.org member
 
Name: Tim
Location: NJ
Join Date: Sep 2013

Motorcycle(s): 2006 Ninja 250

Posts: 41
one cylinder richer than the other

I have a carburetor issue going on (don't most of us do?). The backstory is the bike was sitting in my garage for a while and with the pandemic, it has given me time to revive it. So long story short, I cleaned the carbs out multiple times due to one issue or the other, rebuilt it with new float bowl gasket, new idle mixture screws, o-rings, spring, and washer, and new float needles. I finally had it running great like a month ago.

Did a small road trip to pick up mail at my gf's place, about 60 miles away, then went to my mom's to pick up old mail, about 30 miles away, then on the way home, I lost all power while on the highway and could not rev past 6k RPM and had a real tough time going above 50 mph. I was able to limp it home and I cleaned the carb again. Honestly, no real findings but I did notice my air filter was disintegrated, so I replaced that with a stock style UNI. I took it for a test ride and it was hard to idle when warmed up. I played with the idle screws a bit and right now I currently have it idling decent while warm but it has a hell of a time starting when cold. This wasn't an issue when it was running great.

So my current issue is I have cylinder 1 running much richer at idle than cylinder 2. There was a misfire for sure and with the bike running at idle warmed up (fans kicking on), I have to set the idle screws at 1 turn out on 2 and like half a turn out on 1 for the misfire to go away. I've pulled the plugs to verify this. #2 is a good brown color but #1 is black. I've done a compression test and it is 155 on both cylinders. Checked spark and it fires right. Checked valve timing and it is at the limits of loose where I last set it.

I have a dynojet kit and I theorized that when I put the new filter in, it threw off the jetting so I stepped down the needle height one notch so its on the 3rd notch. I've also set the float height to 19mm, which is also the limit of what the service manual says. I thought maybe the coasting enricher is at fault but I took it apart and the o-ring and diaphragm looks good. Plus I think the design of the enricher throws fuel in both carbs if there is enough vacuum. What else can cause one side of the carb to dump more fuel than the other? Thanks in advance.
crimsondragon is offline   Reply With Quote




Old September 13th, 2020, 03:52 PM   #2
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 crimsondragon View Post
What else can cause one side of the carb to dump more fuel than the other?
One thing would be a leaking or sticking float valve.
Triple Jim is offline   Reply With Quote


Old September 13th, 2020, 05:24 PM   #3
SibSerge
ninjette.org member
 
Name: Sergey
Location: Ontario, GTA
Join Date: Oct 2019

Motorcycle(s): Ninja ZZR250 (EX250H)

Posts: 121
Have you synchronized the carbs ?
SibSerge is offline   Reply With Quote


Old September 13th, 2020, 07:05 PM   #4
DannoXYZ
ninjette.org certified postwhore
 
Name: AKA JacRyann
Location: SF East Bay
Join Date: Dec 2011

Motorcycle(s): CB125T, Ninja250R racer,Ninja250R street EX250F#1 EX250F#2 EX250E CBR250R(MC19) CBR250RR(MC22) VF500F CBR600RR

Posts: A lot.
MOTY - 2018, MOTM - Nov '17
Quote:
Originally Posted by crimsondragon View Post
Did a small road trip to pick up mail at my gf's place, about 60 miles away, then went to my mom's to pick up old mail, about 30 miles away, then on the way home, I lost all power while on the highway and could not rev past 6k RPM and had a real tough time going above 50 mph. I was able to limp it home and I cleaned the carb again.
When it dies like this, is typically caused by dried chunks of petrol varnish being dislodged and clogging bleed-holes in pilot-jet, and/or emulsion-tubes and/or carb-venturi. Note that spray carb cleaners no longer work due to removal of chlorinated compounds.

You’ll have better luck with pee, it has ammonia which does good job of cleaning deposits off aluminium. To really clean carbs requires lots of mechanical scrubbing and flossing of secret hidden fuel-circuits after jets. Also needs hours if soaking in ultrasonic cleaner followed by micro soda-blasting. Do search on here for “clean carbs ducatiman” for photos and procedures on what it takes to restore carbs to factory-fresh clean condition. When carbs are restored to factory-fresh clean, bike will run like brand-new off showroom floor.
DannoXYZ is offline   Reply With Quote


Old September 13th, 2020, 07:40 PM   #5
crimsondragon
ninjette.org member
 
Name: Tim
Location: NJ
Join Date: Sep 2013

Motorcycle(s): 2006 Ninja 250

Posts: 41
Quote:
Originally Posted by DannoXYZ View Post
When it dies like this, is typically caused by dried chunks of petrol varnish being dislodged and clogging bleed-holes in pilot-jet, and/or emulsion-tubes and/or carb-venturi. Note that spray carb cleaners no longer work due to removal of chlorinated compounds.

You’ll have better luck with pee, it has ammonia which does good job of cleaning deposits off aluminium. To really clean carbs requires lots of mechanical scrubbing and flossing of secret hidden fuel-circuits after jets. Also needs hours if soaking in ultrasonic cleaner followed by micro soda-blasting. Do search on here for “clean carbs ducatiman” for photos and procedures on what it takes to restore carbs to factory-fresh clean condition. When carbs are restored to factory-fresh clean, bike will run like brand-new off showroom floor.
When I cleaned it, there was some sort of chunk stuck in the main jet tube after I removed it. I blew it out but never recovered it. I'm not sure if it was a piece of the air filter or a rust particle, or a piece of glue from my disintegrating fuel filter. The test run after that cleaning, I was able to go above 50 mph but it was sluggish and bogging, hence why I adjusted the main needles down a notch.
crimsondragon is offline   Reply With Quote


Old September 14th, 2020, 01:43 AM   #6
DannoXYZ
ninjette.org certified postwhore
 
Name: AKA JacRyann
Location: SF East Bay
Join Date: Dec 2011

Motorcycle(s): CB125T, Ninja250R racer,Ninja250R street EX250F#1 EX250F#2 EX250E CBR250R(MC19) CBR250RR(MC22) VF500F CBR600RR

Posts: A lot.
MOTY - 2018, MOTM - Nov '17
Unless you’ve disassembled carbs down to each and every individual component and scrubbed, poked and flossed them, along with replacing all rubber O-rings and seals, your carbs are not factory-fresh clean. Your bike will run like brand-new model off showroom floor when carbs are factory-fresh clean.

Check out this thread for photos and procedures on how to get carbs factory-fresh clean. Do search here for “clean carbs ducatiman” to find threads with similar symptoms to yours and how to get bike back to brand-new showroom condition.
DannoXYZ is offline   Reply With Quote


Reply




Similar Threads
Thread Thread Starter Forum Replies Last Post
[kropotkin thinks...] - 2018 Sepang MotoGP Race: The Rich Get Richer Ninjette Newsbot Motorcycling News 0 November 3rd, 2018 11:28 PM
One cylinder not firing acook3323 1986 - 2007 Ninja 250R Tech Talk 11 November 6th, 2016 06:11 PM
[motorcycle.com] - Five Minutes With Harley-Davidson Senior VP Mark-Hans Richer Ninjette Newsbot Motorcycling News 0 August 24th, 2015 08:00 PM
Which Master Cylinder should i get? krolinked 2008 - 2012 Ninja 250R Tech Talk 7 January 12th, 2013 01:01 PM
Why is everyone older and richer than me here?... 249cc Off-Topic 41 November 15th, 2012 12:04 AM


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 01:22 AM.


remote server monitor
Powered by vBulletin®
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
User Alert System provided by Advanced User Tagging (Lite) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Except where otherwise noted, all site contents are © Copyright 2020 ninjette.org, All rights reserved.