Idle Mixture Screw Problem

gogoKawi · April 22nd, 2013, 07:08 PM

My soon to be track bike is getting prepped for some thrashing at Summit Point. I did the usual upgrades. I ditched snorkle and kleen air hoses. Put on rearsets, full Yoshi exhaust, K&N, clip-ons, sticky rubber, and jet kit. I have the Factory Pro and DJ Stage 2 kits. I got both by accident.

I decided to go with the DynoJet kit. So I snatched out the carbs after about 2 hours fighting with the darn airbox. I replaced the main jet, which was easy. Then I drilled aluminum coverings to access the idle mixture screws. I backed the screws all the way in and proceeded to adjust them to 2.5 turns to start. The left carb went to 2.5 turns and beyond to about 4.5 turns. The right carb would only go out 2 turns. And by turns, I mean rotated 360 degrees two times. Beyond that, it's very difficult to turn the screw. I didn't want to take any chances turning it beyond that since it became so difficult.

At idle, it runs fine. But when I blip the throttle, the revs hang for about 2 or 3 seconds and then come down slowly. I made sure the throttle cables weren't sticking. Based on what I read, it sound like the idle mixture screws need to be turned out more.

So frustrating... This is my first time working on carbs. I spent about 2 weeks researching just to make sure I understood what I was doing before tearing into things. And I know I'm so close to having this done. My hope was to have the bike done for the track day this weekend. My track plastics came in today. Thanks Richard! But I'm not so sure if the track is going to happen this weekend.

So am I screwed?

vmax · April 23rd, 2013, 02:37 AM

Your idle screw too lean that why when you blip it hang a while, turn your idle screw both 3 turn and put your needles clip at #3 from top

Quote:

Originally Posted by gogoKawi

My soon to be track bike is getting prepped for some thrashing at Summit Point. I did the usual upgrades. I ditched snorkle and kleen air hoses. Put on rearsets, full Yoshi exhaust, K&N, clip-ons, sticky rubber, and jet kit. I have the Factory Pro and DJ Stage 2 kits. I got both by accident.

I decided to go with the DynoJet kit. So I snatched out the carbs after about 2 hours fighting with the darn airbox. I replaced the main jet, which was easy. Then I drilled aluminum coverings to access the idle mixture screws. I backed the screws all the way in and proceeded to adjust them to 2.5 turns to start. The left carb went to 2.5 turns and beyond to about 4.5 turns. The right carb would only go out 2 turns. And by turns, I mean rotated 360 degrees two times. Beyond that, it's very difficult to turn the screw. I didn't want to take any chances turning it beyond that since it became so difficult.

At idle, it runs fine. But when I blip the throttle, the revs hang for about 2 or 3 seconds and then come down slowly. I made sure the throttle cables weren't sticking. Based on what I read, it sound like the idle mixture screws need to be turned out more.

So frustrating... This is my first time working on carbs. I spent about 2 weeks researching just to make sure I understood what I was doing before tearing into things. And I know I'm so close to having this done. My hope was to have the bike done for the track day this weekend. My track plastics came in today. Thanks Richard! But I'm not so sure if the track is going to happen this weekend.

So am I screwed?

tubarney · April 23rd, 2013, 05:17 AM

Your not screwed. Change things and see what effect it has. You won't do any damage playing around with your jetting.

Here's a link that might help you out. Thanks to Chris for the link.

http://www.factorypro.com/tech_tunin...m_engines.html

gogoKawi · April 23rd, 2013, 08:22 AM

Thanks for the replies. I understand that the bike is running lean. The the problem is that I am not able to turn one of the mixture screws beyond 2 rotations to make it run richer. Has anyone had this problem before with not being able to turn the idle mixture screw?

csmith12 · April 23rd, 2013, 08:28 AM

Yea... must be debris in their somewhere. Do a carb soak, blow out with forced air and try again.

menikmati · April 23rd, 2013, 12:00 PM

I think that if you turn the screws out far enough counter-clockwise, that they will eventually come out. As @csmith12 said, there may be some debris or gunk that's preventing the screw from going past 2 turns.

gogoKawi · April 23rd, 2013, 07:07 PM

Took the carbs off again (which I've got really good at) and hit the idle screw with the air compressor. Also, dremelled the rest of the aluminum covering from over top of the idle mixture screws. What that allowed me to do was to insert a full length screwdriver and turn the stubborn screw with some pressure. I was able to turn it enough. Unfortunately, the air blowing didn't help. The screw became hard to turn after about 3 turns, which was enough to get the bike running decently.

Now it's time to tune it!

April 22nd, 2013, 07:08 PM	#1
gogoKawi ninjette.org sage Name: Dre Location: DMV Join Date: Aug 2009 Motorcycle(s): 2014 Ninja 300, 2008 ZX6, 2011 Ninja 1000 Posts: 622	Idle Mixture Screw Problem My soon to be track bike is getting prepped for some thrashing at Summit Point. I did the usual upgrades. I ditched snorkle and kleen air hoses. Put on rearsets, full Yoshi exhaust, K&N, clip-ons, sticky rubber, and jet kit. I have the Factory Pro and DJ Stage 2 kits. I got both by accident. I decided to go with the DynoJet kit. So I snatched out the carbs after about 2 hours fighting with the darn airbox. I replaced the main jet, which was easy. Then I drilled aluminum coverings to access the idle mixture screws. I backed the screws all the way in and proceeded to adjust them to 2.5 turns to start. The left carb went to 2.5 turns and beyond to about 4.5 turns. The right carb would only go out 2 turns. And by turns, I mean rotated 360 degrees two times. Beyond that, it's very difficult to turn the screw. I didn't want to take any chances turning it beyond that since it became so difficult. At idle, it runs fine. But when I blip the throttle, the revs hang for about 2 or 3 seconds and then come down slowly. I made sure the throttle cables weren't sticking. Based on what I read, it sound like the idle mixture screws need to be turned out more. So frustrating... This is my first time working on carbs. I spent about 2 weeks researching just to make sure I understood what I was doing before tearing into things. And I know I'm so close to having this done. My hope was to have the bike done for the track day this weekend. My track plastics came in today. Thanks Richard! But I'm not so sure if the track is going to happen this weekend. So am I screwed?

April 23rd, 2013, 08:28 AM	#5
csmith12 The Corner Whisperer Name: Chris (aka Reactor) Location: Northern KY Join Date: May 2011 Motorcycle(s): 2010 250 (track), 1992 250, 2006 R6 (street/track), 2008 R6 (track) Posts: Too much. MOTY 2015, MOTM - Nov '12, Nov '13	Yea... must be debris in their somewhere. Do a carb soak, blow out with forced air and try again. __________________________________________________ Goal: Shake A Million Hands \| Look through the corners \| Track Day Prep \| Closest track? \| The Mid-Ohio School

April 23rd, 2013, 12:00 PM	#6
menikmati crash 250, get supersport Name: Richard Location: San Diego, CA Join Date: Apr 2010 Motorcycle(s): 2010 250R SE (Sold 6/9/14), 2009 ZX-6R (Sold 6/25/14), Subaru BRZ Posts: A lot.	I think that if you turn the screws out far enough counter-clockwise, that they will eventually come out. As @csmith12 said, there may be some debris or gunk that's preventing the screw from going past 2 turns. __________________________________________________

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April 23rd, 2013, 05:17 AM	#3
tubarney ninjette.org sage Name: Brad Location: Sydney Join Date: Mar 2012 Motorcycle(s): Ninja 250r 2010 SE Posts: 573	Your not screwed. Change things and see what effect it has. You won't do any damage playing around with your jetting. Here's a link that might help you out. Thanks to Chris for the link. http://www.factorypro.com/tech_tunin...m_engines.html

April 23rd, 2013, 08:22 AM	#4
gogoKawi ninjette.org sage Name: Dre Location: DMV Join Date: Aug 2009 Motorcycle(s): 2014 Ninja 300, 2008 ZX6, 2011 Ninja 1000 Posts: 622	Thanks for the replies. I understand that the bike is running lean. The the problem is that I am not able to turn one of the mixture screws beyond 2 rotations to make it run richer. Has anyone had this problem before with not being able to turn the idle mixture screw?

April 23rd, 2013, 07:07 PM	#7
gogoKawi ninjette.org sage Name: Dre Location: DMV Join Date: Aug 2009 Motorcycle(s): 2014 Ninja 300, 2008 ZX6, 2011 Ninja 1000 Posts: 622	Took the carbs off again (which I've got really good at) and hit the idle screw with the air compressor. Also, dremelled the rest of the aluminum covering from over top of the idle mixture screws. What that allowed me to do was to insert a full length screwdriver and turn the stubborn screw with some pressure. I was able to turn it enough. Unfortunately, the air blowing didn't help. The screw became hard to turn after about 3 turns, which was enough to get the bike running decently. Now it's time to tune it!