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Discussion Starter #1 (Edited)
Intake issues? 2008 ZX6R SOLVED

So new to the ZX6R, but I'm experienced mechanically with the Ninja 250.
Last sunday I rode my bike from my home to school, about 4 hours. First big ride on the ZX6R and it was miserably cold but I loved every second of it. Ran perfect the whole way here. All week it's been cold but I have been running it every couple days for a half hour or so, still running good.
Yesterday I took it out for a longer ride, maybe an hour or so running great.
About 4 hours after that I hopped on to go for a late night taco bell run and I fire it up in neutral, idle is fine. I drop it in gear and accelerate, but pull in the clutch because I have to do a U turn. Bike chugs and dies, figure it was cold, fire it back up. Idles fine. Apply throttle and get to the stop sign by the road. Pull in clutch, dies again.


Basically, bike dies if I don't give it throttle. If I give it throttle it runs perfectly. Throttle response and return is perfect. Seems to die whether it's a cold engine or warm.

No ECU error displayed.
Bike has about 16.5k miles on it. It's probably due for a valve servicing. I intend to do so as soon as the motorcycle shop can have me in. I'd do it but not without a garage here.

I thought maybe that the idle speed was too low (it's around 1700, so it's not), but spinning the idle adjustment screw doesn't adjust the idle speed at all. I don't know how the idle adjustment works on an EFI system, but maybe that's a problem?

I'm thinking about limping it to fleet farm to get some fuel system cleaner and try that, but it's fresh gas seeing how I went through 2 tanks to get to Menomonie on Sunday.

I'm completely overwhelmed with how to troubleshoot this. I've always worked with a carb (albeit a shitty carb that had to be rebuilt every 6 months). If my ECU doesn't bring up an error that rules out it being some sort of fuel mixture problem right?

TLDR: 4 hours after a good ride, bike chugs out at idle unless throttle is applied. If throttle is applied then bike runs fine.

Edit: I forgot to mention that my buddy put smog block-off plates on the bike as well as having done the jumper mod. I don't know anything about either of them or if they could cause this. Said that something like this happened once before like a year ago after having done these modifications but the problem went away the next day. The next time I go home I might get rid of the block-off plates and see if that helps.
 

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Discussion Starter #3 (Edited)
Does the fi light work try pulling codes and see if one pops up this sounds really strange
I held the mode button for 2 seconds with the odo up and nothing popped up. I guess that doesn't prove that the FI light works or not, I've never had anything show up before.


The more I think about it the more I'm leaning towards the valves being tight. I'm going to get them done for sure anyways because of the service recommendation, maybe they'll turn out to be the issue.


Edit: I forgot to mention that my buddy put smog block-off plates on the bike as well as having done the jumper mod. I don't know anything about either of them or if they could cause this. Said that something like this happened once before like a year ago after having done these modifications but the problem went away the next day. The next time I go home I might get rid of the block-off plates and see if that helps.
 

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on my bike the clacking sound when key is turned to start is secondary butterflies opening and closing to ensure operability, the constant hum is the fuel pump. it sounds like you may have some foreign matter blocking your throttle bodies somewhere as your idle adjustment screw (if it works the same as my year) doesnt do anything and your idle is on the high side. something may be sticking your primary or secondary butterflies open a little and blocking air moving through causing it to die, but that is just an educated guess.
 

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Discussion Starter #8
on my bike the clacking sound when key is turned to start is secondary butterflies opening and closing to ensure operability, the constant hum is the fuel pump. it sounds like you may have some foreign matter blocking your throttle bodies somewhere as your idle adjustment screw (if it works the same as my year) doesnt do anything and your idle is on the high side. something may be sticking your primary or secondary butterflies open a little and blocking air moving through causing it to die, but that is just an educated guess.
I was more questioning the squeaking sound.

Anyways, here's what happens when I start the bike in neutral.

https://plus.google.com/118289915555086745022/posts/DnorFwSHVJy

It will not die if I hold the throttle open a little bit.

However, if it's the first start of the day, it seems like it will idle in neutral for at least over a minute. Only after I flip it in gear and move it around will it die when I let go of the throttle.

Also, do I have to pull this

off to get at the air filter? The manual says I don't have to but I couldn't pull the upper part off.
 

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it kinda looks like in that video that your idle is just set too low. upon start up your bike puts the rpms somewhere about 1700 like you were saying but then it lets it drop back to wherever the physical idle stop is at... you were saying that your idle adjustment knob doesnt do anything? are you talking about the one below the seat? also as far as airbox removal i think those are the secondary injectors (my bike doesnt have) it looks like you should be able to pull the top of the box up and over without unhooking the fuel rail... they are just injectors that spray into your airbox. make sure you remember to get the bolt down in the middle of the airbox cover.
 

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if you can get the airbox lid off you can look down into the throttle bodies for any obstructions but form your video its looking to me just like your idle is set too low... on my bike theres not really a computer controlled "choke" effect where the computer upon start holds the idle up higher when cold. (why upon cold start it lasts longer than upon subsequent starts.) your bike i assume does as its newer. this is just like in your car when you crank it up the rpms go up to like 1500 say and then after a few seconds drop closer to normal idle speed. have you tried turning your idle knob the other way? lol
 

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Discussion Starter #11 (Edited)
if you can get the airbox lid off you can look down into the throttle bodies for any obstructions but form your video its looking to me just like your idle is set too low... on my bike theres not really a computer controlled "choke" effect where the computer upon start holds the idle up higher when cold. (why upon cold start it lasts longer than upon subsequent starts.) your bike i assume does as its newer. this is just like in your car when you crank it up the rpms go up to like 1500 say and then after a few seconds drop closer to normal idle speed. have you tried turning your idle knob the other way? lol
Yeah I know what you're saying, it's just that no matter how far i spin the idle adjustment either way it doesn't seem to do anything. I don't know which direction to turn it to turn it up.

Yeah I'm turning the screw below the seat on the left side.

There was a bolt in the middle of the cover? I didn't see it. My manual showed 9 screws and I got nine from around the rim.
Damnit, I just watched a video and the first comment on youtube says "you forgot to mention the screw in the middle"
Would have been really nice if the service manual would have actually shown a good illustration for that.


The more I read about vacuum tube issues the more I feel like that's what's wrong. The only vacuum tube I need to look at is the one on the right side of the airbox right below the air pressure sensor right?
 

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Discussion Starter #12 (Edited)
Update: I'm an idiot edition.

Pulled airbox open, filter looks mint.
Inspected vacuum tube, feels operational.
Inspected idle adjustment mechanism, looks operational.
Bolt it all back up, idle it to 200 F.
Run it around the block, problem is gone.

My first guess is that I may or may not have turned the idle all the way down on accident. Need to wait for bike to cool and test it to be sure. If the problem happens again when the system is cold, I'm going to at least have an idea of what might be wrong here. If not, I'm indeed a complete idiot and I will close this thread.

Thank you all for the help that you've given me.

So it's fine now I must have messed up the idle speed.

Dunno how to close threads so I'll just put solved in the title.
 
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