Hey Brad saw your video and I was having the same exact problem. I have an 05 450 YFZ and 04 450 YFZ. I constantly had problems with the carb on the 05, but the carb on the 04 ran perfect, so what I did is I took both of them apart to compare and set the 05 to match the 04. On the 04 the carb slide did not have an O seal on the plate but the 05 did, so I took it off. I put them both back together and reinstalled them, the 04 ran great w/ little adjustment, but the 05 kept coughing and also hanging up on throttle. After much adjustment no success, so I took it back out and noticed that the slide had a lot of play or slap, so I reinstalled the O seal on slide and tightened the starter plunger cap "snug" (the black plastic hex nut on top of the carb) reinstalled the carb. That solved my problem, it idles great after warm up and throttle does not hang. So check the O seal on your slide if it is not cracked or torn take it off and flip it over and reinstall that should take most of the slap in the slide. Hope this info works for you.
That sound you're here when the quad is off at the beginning of the video is the pump shot that's connected on the butterfly of the throttle. Look up the zip tie mod easy to do and you will have better throttle response
I see the video is old but if you still have the YFZ, I would suspect a lean running issue, i.e. Air leak or to lean on the jets and mix screws, it would also explain when the motors hot the issue happens, everything leans out when the motors hot. Hope this helps
If u havent fixed ur high idle speed problem, from what it looks like from the video is your carb slide getting stuck after u punch the gas. check the slide mounting.
Sorry to revive the dead here. I have an 06 Bill Balance edition, with an Edelbrock 9097 slide carb that does something similar. It used to be I could blip the throttle and it would hang. I took the carb apart and cleaned everything. The biggest sticky part was the accelerator pump. Took it for a ride today. Now it hangs when going down a steep hill, or for a little bit after riding through rough/bumpy terrain. I'm wondering if the float is set to high, and it is slobbering fuel up in to the carb throat.
You don't need to turn it off though, if you are riding it and u stop and its idling high, just pop it into gear and just let off the clutch slow(not all the way, usually till it starts trying to move) and it will go away, but it only fixes it until u stop again
maybe your idle adjustement is set too high. when your motor is warmed up (at least 10min of riding) set your idle down until the motor want to stop and then turn it up a little bit. i don't know if it will fix your problem but it has fixed mine! when the idle is adjusted too high, the idle at cold start seem to be normal but when the motor get hot, you can have symptom of a lean pilot jet. if not , try a leak test at your carbs boots with break cleaner or something like that.
its your air fuel mixture screw thats off, on these hight performace 4 strokes every thing needs to be just right temperature and altitude can effect the way carbs work adjust you air fuel mixture screw itlll work
No. I have the new billet throttle and new cable installed. Same issue when warm. It has to be something mechanical in the carb...? Not sure where to start.
i've heard that its a problem with the pilot jet because i have the same issue with a 2001 wr250f, havn't fixed it yet, but thats only what ive read from other places on the internet.. hope you figure it out. if i do... i'll let you know
Did you figure it out? I have the same hanging Idle problem on my CRF...To all people out there that don't know shit don't post please....ITS NOT THE IDLE SCREW......
have the same problem on my Yamaha xs650 twin and its driving me nuts. Bike stored for past year due to this hanging idle problem. Cleaned and checked both carbs a dozen times and still can't figure it out. My feeling now is that it is either the slide/s staying up and not returning or its a leaking sticking exhaust inlet valve not seating when hot ? either way the engine is drawing too much fuel and air keeping the slide up and pulling too much fuel from the needle jet . It can't be an air leak or the idle would stay high when you let the clutch out slowly in gear or you restart the engine but it doesn't .The idle returns to normal until the throttle is blipped again Next test I'm going to pull the pods off and watch what happens to the throttle slides when the idle is hanging. th-cam.com/video/m0LJ81ik1CQ/w-d-xo.html
Wow so 11 years has passed and no one was able to figure this out?
Hey Brad saw your video and I was having the same exact problem. I have an 05 450 YFZ and 04 450 YFZ. I constantly had problems with the carb on the 05, but the carb on the 04 ran perfect, so what I did is I took both of them apart to compare and set the 05 to match the 04. On the 04 the carb slide did not have an O seal on the plate but the 05 did, so I took it off. I put them both back together and reinstalled them, the 04 ran great w/ little adjustment, but the 05 kept coughing and also hanging up on throttle. After much adjustment no success, so I took it back out and noticed that the slide had a lot of play or slap, so I reinstalled the O seal on slide and tightened the starter plunger cap "snug" (the black plastic hex nut on top of the carb) reinstalled the carb. That solved my problem, it idles great after warm up and throttle does not hang. So check the O seal on your slide if it is not cracked or torn take it off and flip it over and reinstall that should take most of the slap in the slide. Hope this info works for you.
That sound you're here when the quad is off at the beginning of the video is the pump shot that's connected on the butterfly of the throttle. Look up the zip tie mod easy to do and you will have better throttle response
I see the video is old but if you still have the YFZ, I would suspect a lean running issue, i.e. Air leak or to lean on the jets and mix screws, it would also explain when the motors hot the issue happens, everything leans out when the motors hot. Hope this helps
If u havent fixed ur high idle speed problem, from what it looks like from the video is your carb slide getting stuck after u punch the gas. check the slide mounting.
Sorry to revive the dead here. I have an 06 Bill Balance edition, with an Edelbrock 9097 slide carb that does something similar. It used to be I could blip the throttle and it would hang. I took the carb apart and cleaned everything. The biggest sticky part was the accelerator pump. Took it for a ride today. Now it hangs when going down a steep hill, or for a little bit after riding through rough/bumpy terrain. I'm wondering if the float is set to high, and it is slobbering fuel up in to the carb throat.
Did you figure it out?
Y’all fixed it yet or no?! I’m running into the same problem rn. Can’t find a solution
Yes i cleaned the carb... All good now... It was super easy ...
why would u play music when we r trying to hear the quad runing?
You don't need to turn it off though, if you are riding it and u stop and its idling high, just pop it into gear and just let off the clutch slow(not all the way, usually till it starts trying to move) and it will go away, but it only fixes it until u stop again
My idle is still a tad high (not as bad as in the video) I have not ripped it down yet. I will let you know what I find when I do...
maybe your idle adjustement is set too high. when your motor is warmed up (at least 10min of riding) set your idle down until the motor want to stop and then turn it up a little bit. i don't know if it will fix your problem but it has fixed mine! when the idle is adjusted too high, the idle at cold start seem to be normal but when the motor get hot, you can have symptom of a lean pilot jet.
if not , try a leak test at your carbs boots with break cleaner or something like that.
its your air fuel mixture screw thats off, on these hight performace 4 strokes every thing needs to be just right temperature and altitude can effect the way carbs work adjust you air fuel mixture screw itlll work
No. I have the new billet throttle and new cable installed. Same issue when warm. It has to be something mechanical in the carb...? Not sure where to start.
No it still acts that way. What are you thinking Bryan?
Just wondering if u ever fixed it and what the problem was
Hi Brad wat did you on your yfz 450 quad, mine has the same problem.. High hanging idle issue when punching the throttle.. Please any advise?
hey there did u ever fix the problem......
i've heard that its a problem with the pilot jet because i have the same issue with a 2001 wr250f, havn't fixed it yet, but thats only what ive read from other places on the internet..
hope you figure it out. if i do... i'll let you know
How did you make out?
Did u ever fix this? Having the same problem.
I had the same problem the issue is from the celblater u need to clean it
did you ever find out what it was?
your throttle cable wire could be frayed causing it to catch after hitting throttle
Have same problem did you figure out what’s wrong
did you ever figure it out?
Found the fix?
Did you ever get this problem fixed?
Did you ever figure out what the problem was? Mine is doing same thing? Let me know please...
It's the carburetor mine does the same
Have you fixed the issue?
Did you figure it out? I have the same hanging Idle problem on my CRF...To all people out there that don't know shit don't post please....ITS NOT THE IDLE SCREW......
Nice bike
What jets do you have in it
I have the same problem with my yfz450 05 you have to jet it to your elevation it's running to lean
All I hear is that dumb music
Don’t put music
have the same problem on my Yamaha xs650 twin and its driving me nuts. Bike stored for past year due to this hanging idle problem. Cleaned and checked both carbs a dozen times and still can't figure it out.
My feeling now is that it is either the slide/s staying up and not returning or its a leaking sticking exhaust inlet valve not seating when hot ? either way the engine is drawing too much fuel and air keeping the slide up and pulling too much fuel from the needle jet .
It can't be an air leak or the idle would stay high when you let the clutch out slowly in gear or you restart the engine but it doesn't .The idle returns to normal until the throttle is blipped again
Next test I'm going to pull the pods off and watch what happens to the throttle slides when the idle is hanging.
th-cam.com/video/m0LJ81ik1CQ/w-d-xo.html
i how whats wong
Tps