Won't idle when warm

PSM · 03-25-2016, 02:32 PM

Hello I have a 2000 gz250 with 15,364 miles that's driving me crazy lol. I've been working on my own bikes for as long as I can remember so I know a bit about fixing these things. Soon as the engine gets warm it won't idle for more then 10-15 seconds. It will idle hi or normal and then just gets slower and slower till it dies. It starts right up but the more it dies the harder it gets to restart. I've cleaned the carb a dozen times at this point and made sure the pilot jet is perfectly clean. So I know that's not the problem and I've sprayed carb cleaner all over the place will engine's running with no results so I know there's no air leaks. I've also check the petcock to make sure it's working right and it is. So what am I missing? I can't think of anything else that would cause this. Usually I clean the carb or replace a leaky hose and it fixes the problem every time know matter what bike i'm working on but this time no such luck. Any help would be greatly appreciated! Thanks!

alantf · 03-25-2016, 03:58 PM

Have you checked that the choke isn't stuck in the "on" position?

PSM · 03-25-2016, 04:34 PM

Yes I made sure it moved freely once installed.

PSM · 03-25-2016, 04:49 PM

I forgot to mention that you can ride it and it's fine but when you come to a red light and it's just at idle it will die if you don't blip the throttle

blaine · 03-25-2016, 08:07 PM

Quote:

Originally Posted by PSM

I forgot to mention that you can ride it and it's fine but when you come to a red light and it's just at idle it will die if you don't blip the throttle

That sure sounds like something wrong in the idle circuit.It the pilot screw o-ring spring & washer in good shape??

PSM · 03-26-2016, 12:27 PM

Just dbl checked and yes the pilot screw, spring, washer, and o-ring are it great shape. Whats the purpose of the diaphragm under the 2 screws on the side of the carb? I've never seen anything like it before. I previously had to replace the diaphragm cause the old one had a whole and it caused the idle to be all over the place so I know it adds air to something.

Water Warrior 2 · 03-26-2016, 12:43 PM

Have you tried adjusting the idle upwards a bit? Sounds like a silly question but it may just be set too low to begin with.

PSM · 03-26-2016, 01:22 PM

Nothing's silly at this point but yes I've tried that. If you turn the idle up high enough it will stop the problem but then the engine is screaming like it's going a 100mph standing still lol

alantf · 03-26-2016, 01:40 PM

It's supposed to be 1200 to 1400 RPM with a HOT engine.

PSM · 03-26-2016, 02:01 PM

Not having a tach on the bike I have to set it by ear but being around bikes all my life I can tell when it's right or at least as close as it can be.

03-25-2016, 02:32 PM	#1
PSM Junior Member Join Date: Mar 2016 Posts: 9	Won't idle when warm Hello I have a 2000 gz250 with 15,364 miles that's driving me crazy lol. I've been working on my own bikes for as long as I can remember so I know a bit about fixing these things. Soon as the engine gets warm it won't idle for more then 10-15 seconds. It will idle hi or normal and then just gets slower and slower till it dies. It starts right up but the more it dies the harder it gets to restart. I've cleaned the carb a dozen times at this point and made sure the pilot jet is perfectly clean. So I know that's not the problem and I've sprayed carb cleaner all over the place will engine's running with no results so I know there's no air leaks. I've also check the petcock to make sure it's working right and it is. So what am I missing? I can't think of anything else that would cause this. Usually I clean the carb or replace a leaky hose and it fixes the problem every time know matter what bike i'm working on but this time no such luck. Any help would be greatly appreciated! Thanks! Login or Register to Remove Ads
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03-25-2016, 03:58 PM	#2
alantf Senior Member Join Date: Nov 2008 Location: Tenerife (Spain) Posts: 3,715	Have you checked that the choke isn't stuck in the "on" position? __________________ By birth an Englishman, by the grace of God a Yorkshireman.
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03-25-2016, 04:34 PM	#3
PSM Junior Member Join Date: Mar 2016 Posts: 9	Yes I made sure it moved freely once installed. Login or Register to Remove Ads
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03-26-2016, 01:40 PM	#9
alantf Senior Member Join Date: Nov 2008 Location: Tenerife (Spain) Posts: 3,715	It's supposed to be 1200 to 1400 RPM with a HOT engine. __________________ By birth an Englishman, by the grace of God a Yorkshireman.
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03-25-2016, 04:49 PM	#4
PSM Junior Member Join Date: Mar 2016 Posts: 9	I forgot to mention that you can ride it and it's fine but when you come to a red light and it's just at idle it will die if you don't blip the throttle
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03-26-2016, 12:27 PM	#6
PSM Junior Member Join Date: Mar 2016 Posts: 9	Just dbl checked and yes the pilot screw, spring, washer, and o-ring are it great shape. Whats the purpose of the diaphragm under the 2 screws on the side of the carb? I've never seen anything like it before. I previously had to replace the diaphragm cause the old one had a whole and it caused the idle to be all over the place so I know it adds air to something.
	0

03-26-2016, 12:43 PM	#7
Water Warrior 2 Senior Member Join Date: Dec 2006 Location: Squamish B.C Canada Posts: 11,409	Have you tried adjusting the idle upwards a bit? Sounds like a silly question but it may just be set too low to begin with.
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03-26-2016, 01:22 PM	#8
PSM Junior Member Join Date: Mar 2016 Posts: 9	Nothing's silly at this point but yes I've tried that. If you turn the idle up high enough it will stop the problem but then the engine is screaming like it's going a 100mph standing still lol
	0

03-26-2016, 02:01 PM	#10
PSM Junior Member Join Date: Mar 2016 Posts: 9	Not having a tach on the bike I have to set it by ear but being around bikes all my life I can tell when it's right or at least as close as it can be.
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