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I have a 2006 with idle issues. It runs just fine, but if I pull in the clutch at speed and let off the throttle the rpms don't come down (in fact sometimes it revs out of control). This also happens if the bike is in neutral and I rev it up - the rpms run away. When this happens, the only way to bring the rpms back down is to put it in gear, let out the clutch a bit, and use an engine load to bring the revs back down. Then it idles just fine.
I just did a carb rebuild - replaced all the jets, seats, gaskets, etc. It's not a sticky cable or the idle speed setting.
Any ideas?

Thanks.
 

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How many turns is the air/fuel screw turned out? Did it do this before the carb rebuild? You cleaned or replaced ALL the jets, including the pilot jet? What size were the jets and what are they now?
 
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I have a 2006 with idle issues. It runs just fine, but if I pull in the clutch at speed and let off the throttle the rpms don't come down (in fact sometimes it revs out of control). This also happens if the bike is in neutral and I rev it up - the rpms run away. When this happens, the only way to bring the rpms back down is to put it in gear, let out the clutch a bit, and use an engine load to bring the revs back down. Then it idles just fine.
I just did a carb rebuild - replaced all the jets, seats, gaskets, etc. It's not a sticky cable or the idle speed setting.
Any ideas?
Mozart2, I had a similar problem and I think it really is about cleaning the circuits in the carb really well. I ran my carb through a ultrasonic cleaner several times and that helped a lot. I also found that the small spring on top of the needle was missing as well. They do sometimes fly across the room when you take them apart. Best wishes for success!

See my earlier thread on this subject:
http://tw200forum.com/forum/technical-help/16206-missing-part-may-cause-slow-return-idle.html
 

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Discussion Starter #4
Yep, replaced all jets including the pilot jet - all with stock size. The air/fuel screw is turned out 1-3/4 as I understand that is the factory setting. The idling problem existed before the rebuild (I was hoping the rebuild would fix it but to no avail).
 

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Open the air/fuel mixture to 2 and 1/2. and see what happens.
 
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Hey Little Tommy,
I've gotten past my CDI problem and now the issue is after totally cleaning the carb i think its out of whack adjustment wise. When cold if i try to use the choke it wont start, like no gas. I've had to start it with putting gas in the cylinder per elime. once started the idle is good but if i pull the choke at all it dies. Went out riding and can wind it out so i runs great so i'm close but dont want to try adjusting my way into screwing it up.
Enjoy Thanksgiving folks
Hertha
 

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I worked on an Yamaha XS500 that had this "hanging idle" problem and it ended up being a valve clearance issue, which seems odd but once they were set to factory specs, it idled fine. Might be worth checking if you haven't already. A vacuum leak will also cause this.
 

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Hey Little Tommy,
I've gotten past my CDI problem and now the issue is after totally cleaning the carb i think its out of whack adjustment wise. When cold if i try to use the choke it wont start, like no gas. I've had to start it with putting gas in the cylinder per elime. once started the idle is good but if i pull the choke at all it dies. Went out riding and can wind it out so i runs great so i'm close but dont want to try adjusting my way into screwing it up.
Enjoy Thanksgiving folks
Hertha
Hertha, I forget, what year is this bike? Is the air/fuel mixture screw out 2 and 1/2 or so? Did it work fine before messing with the carb? Did you add shims or change anything? Were there any parts left over? ha ha I want to think the problem is in your pilot jet or associated parts.... Tell us more please, we'll do our best.
 

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Hey Little Tommy and Scotti,
Its an 87, just well cleaned new gaskets. it runs awesome once started idling with the expected bump bump bump no choke at a traffic light ran it up well over 60 yesterday no hitch just very low(maybe too low idle). no shims and no left over parts BAHHHHHH did look for that wouldnt be the first time. Will run the screw to the bottom and get to 2 1/2 again. Just crazy drop some gas in cylinder and from then on running tight. Appreciate y'alls time. Need to get it together before too cold to work in driveway.
later hertha
 

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Hey Little Tommy and Scotti,
Its an 87, just well cleaned new gaskets. it runs awesome once started idling with the expected bump bump bump no choke at a traffic light ran it up well over 60 yesterday no hitch just very low(maybe too low idle). no shims and no left over parts BAHHHHHH did look for that wouldnt be the first time. Will run the screw to the bottom and get to 2 1/2 again. Just crazy drop some gas in cylinder and from then on running tight. Appreciate y'alls time. Need to get it together before too cold to work in driveway.
later hertha
Just confirmed 2 1/2 still the same turning over but no joy. Dont know if putting gas in the cylinder will help me get to figuring this out. thx hertha
 

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My guess is you have a vacuum leak. I would further guess that it's on the intake boot, the part between the carb and the cylinder.
Here's why;
When you open the throttle, the butterfly valve opens and air is allowed in. With throttle closed, the butterfly valve is also closed, no air other than the hole for the pilot circuit. So, for the motor to rev, it's gotta have air. This air has to also somehow be sensed in the carb as a low pressure and suck fuel. The only place I can think that could happen is on that boot. That it doesn't happen other than when you pull a very strong vacuum; a high rpm throttle chop with no load on the motor, indicates that the leak is probably usually sealed under normal conditions, like a rip in the rubber; fine normally, leaks under vacuum.
So I would start there. Check it over very carefully, flex it to look for cracks. In the meantime, here's some reading for you;

http://tw200forum.com/forum/technical-help/5510-intake-boot.html

http://tw200forum.com/forum/technical-help/16206-missing-part-may-cause-slow-return-idle.html

http://tw200forum.com/forum/technical-help/14298-another-hanging-idle-issue.html
 

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Just confirmed 2 1/2 still the same turning over but no joy. Dont know if putting gas in the cylinder will help me get to figuring this out. thx hertha
Hertha, I don't know. Try SkiPro's suggestion. Hopefully a few more folks will have some ideas. Sorry Hertha...
 

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Hey All, thanks for ideas, forgot to hit back last weekend on this tried to use wd40 on the intake with it running to see if it would lag highlighting a crack. it didnt. started yesterday (again with a bit of gas in cylinder) road to work, home ran an errand no issue. Couldnt check today shitty weather cold and rainy (no garage). Will probably remove boot and look for cracks like ski pro suggested, my old timer eyes didnt see anything gross as a crack. thanks for your time. hertha
 

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Hey All,
Hertha's Ambulance service bunch of time between posts... Finally had some dry weather, took off the carb and found i set the idle screw incorrectly. Once i "closed" it it starts without the priming but slow idle. Think i'm close since once it warms up it it runs great. Ran around yesterday winded it out with no backfire, but still cant use the choke at all. (but its in the 60's here near DC so maybe thats correct)
thx for ideas.
 

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Hey All,
Hertha's Ambulance service bunch of time between posts... Finally had some dry weather, took off the carb and found i set the idle screw incorrectly. Once i "closed" it it starts without the priming but slow idle. Think i'm close since once it warms up it it runs great. Ran around yesterday winded it out with no backfire, but still cant use the choke at all. (but its in the 60's here near DC so maybe thats correct)
thx for ideas.
If it doesn't sound like it used to at idle, turn it up a bit. True, you may need no choke at those temps. ;)
 

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Hey little tommy, thx brother, have final got back to steady state (actually been there for a couple weeks), beast is running fine. a little finicky on start but fires up (sort of cold blooded even tho its in the 90s). really appreciate the advice and encouragement. thx hertha
 

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You are welcome Hertha!! :D
Hey little tommy, thx brother, have final got back to steady state (actually been there for a couple weeks), beast is running fine. a little finicky on start but fires up (sort of cold blooded even tho its in the 90s). really appreciate the advice and encouragement. thx hertha
 
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