Idling when the engine is Hot

slayerman5 · 03-01-2020, 03:47 PM

Ok guys i cleaned my carb in ultra sound bath, i used carb clener sprays, i bought some new carburator parts -diaphragma and diaphragma assy they were not new!
Also bought a O ring for the connection from carburator to engine.
Did a valve clearence.
Checked the Float height also make it correct.
Changed the Voltage regulator,new battery.
And still have a fuking problem, when my motorcycle warms up and i got a Fullthrotle at neutral shift or when i get in a light traffic the idling goes very High, after i change a gear the idling is going stable?
Some one has some idea for this problem it makes me fuking crazy !!!!!!
Tnx alot Folks!

Vegas Street Rider · 03-01-2020, 07:24 PM

You may have an issue with the diaphragm on the back side of the fuel petcock. Mine did the same thing until I rebuilt it with a kit. They cost around $25 to $35 bucks online last time I checked.

slayerman5 · 03-01-2020, 11:19 PM

https://www.motorcyclespareparts.eu/...les/carburetor
i bought a new one and raplace them from №3,38

slayerman5 · 03-01-2020, 11:25 PM

If it's not this can you show me where is that thing

? tnx

Vegas Street Rider · 03-02-2020, 10:21 AM

It is the fuel petcock on your fuel tank. Internally, it has a diaphragm on the backside facing the carburetor. It is connected to your carburetor by a small hose.

How it works is that as you open the throttle, a vacuum is created in the carburetor and that vacuum pulls open the valve which allows more fuel into said carburetor. As you throttle down to idle, less vacuum, thereby the valve closes down to allow less fuel into the carburetor. The internal valve controlled by the movement of that diaphragm could be stuck open due to shellac buildup from the fuel or sediment from the tank.

You could take it apart and clean it or get a repair kit and rebuild it. It is pretty simple to do. Hope this helps you.

slayerman5 · 03-02-2020, 10:41 AM

WOWWWWWWWWWWWWWW dude yea i get it !!!!! i will try tommorow !
I will be so happy if it works !!!! thank you !!!!

slayerman5 · 03-03-2020, 06:00 AM

Ok i cleaned it assemble it again , it was dirty the diaphragm was old but not damaged and the fuking problem is still there, maybe one idea better! There is no vacum leaks because i have starter spray and there is no more than a normal idling when i spray around carburator

slayerman5 · 03-03-2020, 06:01 AM

But i dont have stock exhaust can be this some kind of a problem ? I think no but have to ask , straight pipes with a Db killers.Tnx

Vegas Street Rider · 03-03-2020, 10:44 AM

Straight pipes will change the whole balance of the fuel system. The carburetor requires a certain amount of back pressure to work properly. If the original muffler has been replaced with straight pipes, then that changes everything. The jets in the carb itself will have to be resized and it is something I have not done but use the search engine on this site, as I believe there are a few threads on it where others have done this procedure. Sorry I can't help more, but you should be able to find that info here. Also, talk to someone at your local bike shop and they can probably explain it better than I.

wacio · 03-05-2020, 12:11 AM

Dicking with air box and exhaust is not good, but Your problem is not likely caused by it here. Your bike will run lean (hot) if you made them less restrictive. But it will run and idle. If your bike is not returning to idle - you have sticking slide or throttle. Check is the throttle is returning to stop each time you twist it. Then (if still not returning to idle) take carb off and check if the slide move up and down freely. Very likely something is not assembled right causing slide to stick...Remember - vacuum moves it up - spring moves it down. Vacuum pulls harder than spring so it will open but if spring is not able to return it down - it will not return to idle normally.

03-01-2020, 03:47 PM	#1
slayerman5 Junior Member Join Date: Oct 2019 Posts: 26	Idling when the engine is Hot Ok guys i cleaned my carb in ultra sound bath, i used carb clener sprays, i bought some new carburator parts -diaphragma and diaphragma assy they were not new! Also bought a O ring for the connection from carburator to engine. Did a valve clearence. Checked the Float height also make it correct. Changed the Voltage regulator,new battery. And still have a fuking problem, when my motorcycle warms up and i got a Fullthrotle at neutral shift or when i get in a light traffic the idling goes very High, after i change a gear the idling is going stable? Some one has some idea for this problem it makes me fuking crazy !!!!!! Tnx alot Folks! Login or Register to Remove Ads
	0

03-01-2020, 11:19 PM	#3
slayerman5 Junior Member Join Date: Oct 2019 Posts: 26	https://www.motorcyclespareparts.eu/...les/carburetor i bought a new one and raplace them from №3,38 Login or Register to Remove Ads
	0

03-02-2020, 10:21 AM	#5
Vegas Street Rider Senior Member Join Date: May 2015 Location: Henderson, NV Posts: 1,089	It is the fuel petcock on your fuel tank. Internally, it has a diaphragm on the backside facing the carburetor. It is connected to your carburetor by a small hose. How it works is that as you open the throttle, a vacuum is created in the carburetor and that vacuum pulls open the valve which allows more fuel into said carburetor. As you throttle down to idle, less vacuum, thereby the valve closes down to allow less fuel into the carburetor. The internal valve controlled by the movement of that diaphragm could be stuck open due to shellac buildup from the fuel or sediment from the tank. You could take it apart and clean it or get a repair kit and rebuild it. It is pretty simple to do. Hope this helps you. Login or Register to Remove Ads
	0

03-01-2020, 07:24 PM	#2
Vegas Street Rider Senior Member Join Date: May 2015 Location: Henderson, NV Posts: 1,089	You may have an issue with the diaphragm on the back side of the fuel petcock. Mine did the same thing until I rebuilt it with a kit. They cost around $25 to $35 bucks online last time I checked.
	0

03-01-2020, 11:25 PM	#4
slayerman5 Junior Member Join Date: Oct 2019 Posts: 26	If it's not this can you show me where is that thing ? tnx
	0

03-02-2020, 10:41 AM	#6
slayerman5 Junior Member Join Date: Oct 2019 Posts: 26	WOWWWWWWWWWWWWWW dude yea i get it !!!!! i will try tommorow ! I will be so happy if it works !!!! thank you !!!!
	0

03-03-2020, 06:00 AM	#7
slayerman5 Junior Member Join Date: Oct 2019 Posts: 26	Ok i cleaned it assemble it again , it was dirty the diaphragm was old but not damaged and the fuking problem is still there, maybe one idea better! There is no vacum leaks because i have starter spray and there is no more than a normal idling when i spray around carburator
	0

03-03-2020, 06:01 AM	#8
slayerman5 Junior Member Join Date: Oct 2019 Posts: 26	But i dont have stock exhaust can be this some kind of a problem ? I think no but have to ask , straight pipes with a Db killers.Tnx
	0

03-03-2020, 10:44 AM	#9
Vegas Street Rider Senior Member Join Date: May 2015 Location: Henderson, NV Posts: 1,089	Straight pipes will change the whole balance of the fuel system. The carburetor requires a certain amount of back pressure to work properly. If the original muffler has been replaced with straight pipes, then that changes everything. The jets in the carb itself will have to be resized and it is something I have not done but use the search engine on this site, as I believe there are a few threads on it where others have done this procedure. Sorry I can't help more, but you should be able to find that info here. Also, talk to someone at your local bike shop and they can probably explain it better than I.
	0

03-05-2020, 12:11 AM	#10
wacio Senior Member Join Date: Apr 2016 Location: Illinois Posts: 174	Dicking with air box and exhaust is not good, but Your problem is not likely caused by it here. Your bike will run lean (hot) if you made them less restrictive. But it will run and idle. If your bike is not returning to idle - you have sticking slide or throttle. Check is the throttle is returning to stop each time you twist it. Then (if still not returning to idle) take carb off and check if the slide move up and down freely. Very likely something is not assembled right causing slide to stick...Remember - vacuum moves it up - spring moves it down. Vacuum pulls harder than spring so it will open but if spring is not able to return it down - it will not return to idle normally.
	0