Question about idle mixture screw and low idle flux

daverdfw · May 31st, 2016, 03:58 PM

I have a 2009 250. with a full M4 exhaust, k&N filter and factory pro jet kit with a 110 main installed.

I am trying to get the idle mixture adjustments correct, I have read the DIY but just am needing some clarification.

I have them both at 2.5 turns out. and when I get on the gas in Neutral, the RPMS will drop after letting off the throttle. For about 15 seconds it will hang at 2000RPM , and then drop to around 1100.

If I adjust the screws all the way in, it never misses, the idle just goes up a bunch. So I am curious if this is the normal behavior, or if I need to look at something else? Thanks!

also just as an added bonus, I bought this bike with 3000 miles on it, and I have no idea if the valve clearance has ever been checked.

redsnapper · June 1st, 2016, 10:40 PM

Blip the throttle 1/8 or a little but don't go past 2500rpm, does the idle hang (lean)? or Drop below Idle (rich).

Rev the throttle to 4000-5000RPM and let go.
Does it hang above idle 2000+ RPM (Lean)
Then you need to raise the needle.

daverdfw · June 2nd, 2016, 08:47 PM

Quote:

Originally Posted by redsnapper

Blip the throttle 1/8 or a little but don't go past 2500rpm, does the idle hang (lean)? or Drop below Idle (rich).

Rev the throttle to 4000-5000RPM and let go.
Does it hang above idle 2000+ RPM (Lean)
Then you need to raise the needle.

I will have to try this tomorrow. I think I am at the point where I am trying to get it perfect, and it's probably fine. I sometimes don't know when to quit. Last I recall I have the clip in the 3rd slot with like 2 washers below.

redsnapper · June 2nd, 2016, 10:36 PM

Warming up the bike.

I find letting the bike sit there for X amount of time is the wrong way to adjust things.

It got so hot that the low end was too rich. My bike would never get that hot sitting in traffic or riding. Adjusting the mixture screws perfectly but found when I ride the bike around normal and stop at lights, blipping the throttle (1/8th or less), it dipped below idle. Also would stumble when the light turn green.

Here's what I did to fix it.

#1 Ride bike around normally.
#2 Go home quickly put bike level with the bike still running (Used phone book under side stand).
#3 As fast as possible, Adjust mixture screw and blip throttle 1/8 or less until idle was right.

Keep in mind this is for Idle/low end adjustment.

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May 31st, 2016, 03:58 PM	#1
daverdfw ninjette.org guru Name: David Location: Fort Worth,TX Join Date: Nov 2015 Motorcycle(s): 2009 Ninja 250 Posts: 386	Question about idle mixture screw and low idle flux I have a 2009 250. with a full M4 exhaust, k&N filter and factory pro jet kit with a 110 main installed. I am trying to get the idle mixture adjustments correct, I have read the DIY but just am needing some clarification. I have them both at 2.5 turns out. and when I get on the gas in Neutral, the RPMS will drop after letting off the throttle. For about 15 seconds it will hang at 2000RPM , and then drop to around 1100. If I adjust the screws all the way in, it never misses, the idle just goes up a bunch. So I am curious if this is the normal behavior, or if I need to look at something else? Thanks! also just as an added bonus, I bought this bike with 3000 miles on it, and I have no idea if the valve clearance has ever been checked.

June 1st, 2016, 10:40 PM	#2
redsnapper ninjette.org member Name: Red Snapper XXX Location: Red Snapper City Join Date: Nov 2013 Motorcycle(s): Ninja 250R 2009 Posts: 39	Blip the throttle 1/8 or a little but don't go past 2500rpm, does the idle hang (lean)? or Drop below Idle (rich). Rev the throttle to 4000-5000RPM and let go. Does it hang above idle 2000+ RPM (Lean) Then you need to raise the needle.
	1 out of 1 members found this post helpful.

June 2nd, 2016, 10:36 PM	#4
redsnapper ninjette.org member Name: Red Snapper XXX Location: Red Snapper City Join Date: Nov 2013 Motorcycle(s): Ninja 250R 2009 Posts: 39	Warming up the bike. I find letting the bike sit there for X amount of time is the wrong way to adjust things. It got so hot that the low end was too rich. My bike would never get that hot sitting in traffic or riding. Adjusting the mixture screws perfectly but found when I ride the bike around normal and stop at lights, blipping the throttle (1/8th or less), it dipped below idle. Also would stumble when the light turn green. Here's what I did to fix it. #1 Ride bike around normally. #2 Go home quickly put bike level with the bike still running (Used phone book under side stand). #3 As fast as possible, Adjust mixture screw and blip throttle 1/8 or less until idle was right. Keep in mind this is for Idle/low end adjustment.