Adjusting the Idle Mixture Screw

conrya5 · March 15th, 2013, 05:46 AM

Hi everyone, sorry if this is an over-post, but I could not locate a thread on this topic with recent activity.

I have just shimmed my needles with two washers on each and plan to sync the carbs before adjusting the idle mixture screws.

I know the bike is to be warmed up to operating temperature, but does it matter what the outside air temperature is? Should I adjust the idle mixture screws now (it has averaged 40 degrees Fahrenheit) and then re-adjust as need in the summer time?

2010 Ninja 250r

Yoshimura TRC Slip-On Exhaust
(2) #4 washers on each needle
Plan to remove snorkel
Bike has been taking a long time to warm up (have not had a chance to ride / star-up since I shimmed the needles)

Thanks in advance for your help!

Motofool · March 15th, 2013, 08:08 AM

Adjust them now, but wait for the warmest time of the day.

choneofakind · March 15th, 2013, 08:27 AM

Adjust them now so the bike runs right in the cold, and adjust them later if needed. The idle mix screws are easy to adjust because they're meant to be adjusted when weather changes.

For example, I jetted my bike when it was about 55-60 outside. Then I went to the track later in the summer; it was about 85 and sunny, and I was wringing its neck. It decided to stop idling well because I had the mix screws too far out. I took 30 seconds in the pits, adjusted them in 1/4 turn, and the bike was happy as a puppy the rest of the day. Point is, change them as the weather conditions change so your bike idles the way it should; that's what they're there for.

menikmati · March 15th, 2013, 11:15 AM

Quote:

Originally Posted by choneofakind

Point is, change them as the weather conditions change so your bike idles the way it should; that's what they're there for.

I'm guilty of only tuning them during the summer (around 85F ambient) and leaving them there. I can definitely tell when the weather affects the idle and throttle blips at idle.

conrya5 · March 15th, 2013, 12:27 PM

Thanks for the input everyone. It is cold, windy, and raining/snowing here so looks like I may not get around to doing this today.

I purchased the Milwaukee offset adapter after reading all of the DIY's about carbs and it has made working on the carbs so much easier (possible) while they are on the bike

menikmati · March 15th, 2013, 12:30 PM

Quote:

Originally Posted by conrya5

I purchased the Milwaukee offset adapter after reading all of the DIY's about carbs and it has made working on the carbs so much easier (possible) while they are on the bike

Best tool for 250R carb work IMO. Never had to take my carbs out for jetting thanks to it.

conrya5 · March 15th, 2013, 03:55 PM

I'm adjusting the idle mixture screws now. When I blip the throttle it revs up and returns as it should. When I'm in first gear and it is under load it sputtered a little but does not stall.

Can anyone shed some light on what may be causing this?

choneofakind · March 15th, 2013, 04:13 PM

How much throttle when it sputters a bit? You may be confusing needle height with idle mix.

Also, try this: get the engine up to temp by riding it. Set the the mix screws to 2 turns. Then back them out 1/4 turn at a time until it feels right. You should be around 2.25 turns or 2.5 turns.

conrya5 · March 15th, 2013, 04:17 PM

I guess the term I should have used was when I go to take off in first gear my bike stutters, wants to die, but it does not stall or anything. I turned the idle mixture screws in until the bike wanted to bog down, then backed them out 2 turns.

Starts right up, idles perfectly, is responsive when I rev the the throttle and returns to idle.

choneofakind · March 15th, 2013, 04:48 PM

Try raising the needles by shimming them with some SAE#4 washers. Try 1 under each needle for now, maybe 2 if you feel improvement but feel you need more

conrya5 · March 15th, 2013, 04:57 PM

Quote:

Originally Posted by choneofakind

Try raising the needles by shimming them with some SAE#4 washers. Try 1 under each needle for now, maybe 2 if you feel improvement but feel you need more

I had just shimmed the needles (2) #4 washers underneath each needle. I shimmed them because my bike came with a yoshimura slip-on and was taking a long time to warm up, leading me to believe that my bike is running to lean.

I will have to try and adjust the mixture screws again tomorrow, if it stops snowing/raining... From what I am reading, my bike may still be lean.

The snorkel is also removed.

choneofakind · March 15th, 2013, 04:59 PM

Maybe a bit. But it's not a large issue if you're a little lean at idle because there's no load at idle. It will just be annoying to start etc.

Try turning them out 1/4 turn at a time and see what works best. I've had good luck doing that.

conrya5 · March 15th, 2013, 05:07 PM

I will try that and let you know the results tomorrow. Thanks for the input

mgentz · March 15th, 2013, 05:53 PM

my screws are real easy to adjust. I have these.

http://www.factorypro.com/prod_pages/prodk04.html

conrya5 · March 15th, 2013, 06:37 PM

Quote:

Originally Posted by mgentz

my screws are real easy to adjust. I have these.

http://www.factorypro.com/prod_pages/prodk04.html

ooooh shiny

sure would be very helpful

menikmati · March 15th, 2013, 08:56 PM

Quote:

Originally Posted by mgentz

my screws are real easy to adjust. I have these.

http://www.factorypro.com/prod_pages/prodk04.html

Didn't know such a thing existed, I would totally get one if it wasn't $52 shipped and required removing the carbs (possibly) to get the o-rings out.

mgentz · March 15th, 2013, 09:31 PM

Yea..I paid no where near that.

conrya5 · March 16th, 2013, 05:24 AM

It would be worth paying that much if you are frequently adjusting your mixture screws.

mgentz · March 16th, 2013, 05:57 AM

When the weather changes you should be making adjustments. Thus you should be making frequent changes.

conrya5 · March 16th, 2013, 06:11 AM

Spring and Summer are my only two main seasons for riding.

You said that you paid no where near $52, where did you get them at?

conrya5 · March 16th, 2013, 10:39 AM

Well I have decided to put the stock exhaust back on, the yoshi is too loud for me. I have pulled the carbs out and will clean them today, adjust needles to stock settings, put (1) shim on each needle, sync them and see what happens!

It is snowing here today so no test riding..

Is anyone interested in the Yoshimura TRC Stainless Steel Slip-On? Figured I would ask here before posting in marketplace.

conrya5 · March 17th, 2013, 10:11 AM

Just an update if anyone is interested:

I puled off the carbs and cleaned them. While I had the carbs off I removed one of my shims on each needle for a total of (1) #4 washer (shim) on each needle.

I reset the idel mixture screws to (2) full turns out and re-installed the carbs on the bike.

Re-installed the stock muffler and the snorkel.

I then began to test ride and make small adjustments to the idle mixture screws and the idle knob.

As of now (40 degrees Fahrenheit today) I have the screws 2-1/2 turns out. The bike does not bog down when I go to take off in first gear and it pulls evenly throughout the RPM range. The bike returns to idle (1,300 - 1,500 RPM) after blipping the throttle to about 3,500 RPM.

Thanks again for all of the help

mgentz · March 18th, 2013, 05:03 AM

nice

BTW, I got my adj screws off eBay and made a best offer.

March 15th, 2013, 05:46 AM	#1
conrya5 ninjette.org member Name: Ryan Location: South Eastern, PA Join Date: Jun 2012 Motorcycle(s): 2010 Metalic Island Blue Ninja 250r Posts: 206	Adjusting the Idle Mixture Screw Hi everyone, sorry if this is an over-post, but I could not locate a thread on this topic with recent activity. I have just shimmed my needles with two washers on each and plan to sync the carbs before adjusting the idle mixture screws. I know the bike is to be warmed up to operating temperature, but does it matter what the outside air temperature is? Should I adjust the idle mixture screws now (it has averaged 40 degrees Fahrenheit) and then re-adjust as need in the summer time? 2010 Ninja 250r Yoshimura TRC Slip-On Exhaust (2) #4 washers on each needle Plan to remove snorkel Bike has been taking a long time to warm up (have not had a chance to ride / star-up since I shimmed the needles) Thanks in advance for your help!

March 15th, 2013, 08:08 AM	#2
Motofool Daily Ninjette rider Name: Hernan Location: Florida Join Date: Mar 2011 Motorcycle(s): 2007 Ninja 250 Posts: A lot. MOTY - 2016, MOTM - Dec '12, Jan '14, Jan '15, May '16	Adjust them now, but wait for the warmest time of the day. __________________________________________________ *Motofool* *.................................Never ride faster than your guardian angel can fly* "Mankind is composed of two sorts of men — those who love and create, and those who hate and destroy. Love is the bond between men, the way to teach and the center of the world." - José Martí

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
DIY - Accessing and adjusting idle mixture screws	VeX	2008 - 2012 Ninja 250R Tech Talk	71	December 15th, 2017 03:38 AM
what is the best idle screw mixture	vmax	2008 - 2012 Ninja 250R Tech Talk	9	July 1st, 2017 10:45 AM
adjusting idle mixture screws	james250ninja	1986 - 2007 Ninja 250R Tech Talk	9	September 1st, 2014 10:29 AM
Idle Mixture Screw Problem	gogoKawi	2008 - 2012 Ninja 250R Tech Talk	6	April 23rd, 2013 07:07 PM
Idle Mixture adjustment screw Q	indr	2008 - 2012 Ninja 250R Tech Talk	1	December 2nd, 2010 09:36 PM

March 15th, 2013, 08:27 AM	#3
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	Adjust them now so the bike runs right in the cold, and adjust them later if needed. The idle mix screws are easy to adjust because they're meant to be adjusted when weather changes. For example, I jetted my bike when it was about 55-60 outside. Then I went to the track later in the summer; it was about 85 and sunny, and I was wringing its neck. It decided to stop idling well because I had the mix screws too far out. I took 30 seconds in the pits, adjusted them in 1/4 turn, and the bike was happy as a puppy the rest of the day. Point is, change them as the weather conditions change so your bike idles the way it should; that's what they're there for.

March 15th, 2013, 12:27 PM	#5
conrya5 ninjette.org member Name: Ryan Location: South Eastern, PA Join Date: Jun 2012 Motorcycle(s): 2010 Metalic Island Blue Ninja 250r Posts: 206	Thanks for the input everyone. It is cold, windy, and raining/snowing here so looks like I may not get around to doing this today. I purchased the Milwaukee offset adapter after reading all of the DIY's about carbs and it has made working on the carbs so much easier (possible) while they are on the bike

March 15th, 2013, 03:55 PM	#7
conrya5 ninjette.org member Name: Ryan Location: South Eastern, PA Join Date: Jun 2012 Motorcycle(s): 2010 Metalic Island Blue Ninja 250r Posts: 206	I'm adjusting the idle mixture screws now. When I blip the throttle it revs up and returns as it should. When I'm in first gear and it is under load it sputtered a little but does not stall. Can anyone shed some light on what may be causing this?

March 15th, 2013, 04:13 PM	#8
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	How much throttle when it sputters a bit? You may be confusing needle height with idle mix. Also, try this: get the engine up to temp by riding it. Set the the mix screws to 2 turns. Then back them out 1/4 turn at a time until it feels right. You should be around 2.25 turns or 2.5 turns.

March 15th, 2013, 04:17 PM	#9
conrya5 ninjette.org member Name: Ryan Location: South Eastern, PA Join Date: Jun 2012 Motorcycle(s): 2010 Metalic Island Blue Ninja 250r Posts: 206	I guess the term I should have used was when I go to take off in first gear my bike stutters, wants to die, but it does not stall or anything. I turned the idle mixture screws in until the bike wanted to bog down, then backed them out 2 turns. Starts right up, idles perfectly, is responsive when I rev the the throttle and returns to idle.

March 15th, 2013, 04:48 PM	#10
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	Try raising the needles by shimming them with some SAE#4 washers. Try 1 under each needle for now, maybe 2 if you feel improvement but feel you need more

March 15th, 2013, 04:59 PM	#12
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	Maybe a bit. But it's not a large issue if you're a little lean at idle because there's no load at idle. It will just be annoying to start etc. Try turning them out 1/4 turn at a time and see what works best. I've had good luck doing that.

March 15th, 2013, 05:07 PM	#13
conrya5 ninjette.org member Name: Ryan Location: South Eastern, PA Join Date: Jun 2012 Motorcycle(s): 2010 Metalic Island Blue Ninja 250r Posts: 206	I will try that and let you know the results tomorrow. Thanks for the input

March 15th, 2013, 09:31 PM	#17
mgentz Board Member Name: ... Location: WI Join Date: Dec 2011 Motorcycle(s): 250R (street), 250R (dirt) Posts: A lot.	Yea..I paid no where near that.

March 16th, 2013, 05:24 AM	#18
conrya5 ninjette.org member Name: Ryan Location: South Eastern, PA Join Date: Jun 2012 Motorcycle(s): 2010 Metalic Island Blue Ninja 250r Posts: 206	It would be worth paying that much if you are frequently adjusting your mixture screws.

March 16th, 2013, 05:57 AM	#19
mgentz Board Member Name: ... Location: WI Join Date: Dec 2011 Motorcycle(s): 250R (street), 250R (dirt) Posts: A lot.	When the weather changes you should be making adjustments. Thus you should be making frequent changes.

March 16th, 2013, 06:11 AM	#20
conrya5 ninjette.org member Name: Ryan Location: South Eastern, PA Join Date: Jun 2012 Motorcycle(s): 2010 Metalic Island Blue Ninja 250r Posts: 206	Spring and Summer are my only two main seasons for riding. You said that you paid no where near $52, where did you get them at?

March 16th, 2013, 10:39 AM	#21
conrya5 ninjette.org member Name: Ryan Location: South Eastern, PA Join Date: Jun 2012 Motorcycle(s): 2010 Metalic Island Blue Ninja 250r Posts: 206	Well I have decided to put the stock exhaust back on, the yoshi is too loud for me. I have pulled the carbs out and will clean them today, adjust needles to stock settings, put (1) shim on each needle, sync them and see what happens! It is snowing here today so no test riding.. Is anyone interested in the Yoshimura TRC Stainless Steel Slip-On? Figured I would ask here before posting in marketplace.

March 17th, 2013, 10:11 AM	#22
conrya5 ninjette.org member Name: Ryan Location: South Eastern, PA Join Date: Jun 2012 Motorcycle(s): 2010 Metalic Island Blue Ninja 250r Posts: 206	Just an update if anyone is interested: I puled off the carbs and cleaned them. While I had the carbs off I removed one of my shims on each needle for a total of (1) #4 washer (shim) on each needle. I reset the idel mixture screws to (2) full turns out and re-installed the carbs on the bike. Re-installed the stock muffler and the snorkel. I then began to test ride and make small adjustments to the idle mixture screws and the idle knob. As of now (40 degrees Fahrenheit today) I have the screws 2-1/2 turns out. The bike does not bog down when I go to take off in first gear and it pulls evenly throughout the RPM range. The bike returns to idle (1,300 - 1,500 RPM) after blipping the throttle to about 3,500 RPM. Thanks again for all of the help

March 18th, 2013, 05:03 AM	#23
mgentz Board Member Name: ... Location: WI Join Date: Dec 2011 Motorcycle(s): 250R (street), 250R (dirt) Posts: A lot.	nice BTW, I got my adj screws off eBay and made a best offer.