No idle unless I blip throttle for 7 secs

JGunn · 09-02-2018, 04:21 PM

My 2007 GZ dies at every stop. So, what I've learned to do is after stopping I will ever so lightly blip the throttle until the bike starts idling again. So, I don't have an idling problem per se, it just dies when I immediately close the throttle when coming into a stop sign. Sometimes when the bike dies it is unable to start again and I have to wait about 10 to 20 seconds and then the bike starts fine...only sometimes though. Other times it will die and have no problem starting right away. After riding for 20+ minutes, however, I no longer have this problem and bike rides fine. I've ridden with the bike in PRI and ON on the petcock and that doesn't make a difference. I will say that if I leave the choke on I will not have this problem, however, the bike naturally will idle extremely high. I thoroughly went through the carbs and they look great. I've adjusted the pilot screw AT 1.5 turns, 2.5 turns, and even 3 full turns. Doesn't make a difference either way. Looked for vacuum leaks by spraying starter fluid around the boots. Nothing changed. Rode the bike with the gas cap off to check with bad ventilation. Nothing changed. I even tried bypassing the air cut off valve and that made the bike run worse. Any suggestions would be helpful.
Not sure if it's related but sometimes the turn signals work and sometimes they don't. Just wondering if there's some weird electrical thing going on here that might affect the idle. Thanks.

Vegas Street Rider · 09-02-2018, 06:04 PM

I had erratic idle issues with my 2009 GZ. It turned out that the petcock diaphragm was bad. I rebuilt it and my idle issues stopped. Sometimes it would idle fine and other times it would idle normally and then gradually increase. Sometimes it would just die when I stopped.
Regarding the turn signal problem, spray some electrical contact cleaner behind the switch and see if that takes care of it.

JGunn · 09-02-2018, 06:40 PM

I thought of that but even when I ride the bike on PRI I have an idle problem. PRI as you know bypasses the diaphragm and just let's the gas flow. I guess I'm a little curious why you need a petcock. Is it literally there to stop the gas in case you want to remove the tank. What's the great function of this valve that makes it necessary. Like I said I checked the flow of gas out of the petcock on PRI and it gushes out. I turned it on ON and sucked on the air valve to see if that works and it does.

Vegas Street Rider · 09-02-2018, 09:54 PM

The petcock is designed to open and allow a given amount of fuel to the carburetor to provide the optimum air/fuel mixture based on the amount of vacuum the carburetor generates which is controlled by the throttle valve. If you leave the petcock on prime, the fuel to air ratio would be too high(rich). The diaphragm regulates that flow. Also, the petcock set on the ON position allows you to only run about 2.8 to 3 gallons of fuel out of the tank allowing you to have reserve fuel available when you make the switch to reserve so you are not left high and dry on the road. It does act as a shut-off as well on either the reserve or ON position as there is no vacuum pulling fuel out when the engine isn't running.

09-02-2018, 04:21 PM	#1
JGunn Junior Member Join Date: Jun 2018 Posts: 18	No idle unless I blip throttle for 7 secs My 2007 GZ dies at every stop. So, what I've learned to do is after stopping I will ever so lightly blip the throttle until the bike starts idling again. So, I don't have an idling problem per se, it just dies when I immediately close the throttle when coming into a stop sign. Sometimes when the bike dies it is unable to start again and I have to wait about 10 to 20 seconds and then the bike starts fine...only sometimes though. Other times it will die and have no problem starting right away. After riding for 20+ minutes, however, I no longer have this problem and bike rides fine. I've ridden with the bike in PRI and ON on the petcock and that doesn't make a difference. I will say that if I leave the choke on I will not have this problem, however, the bike naturally will idle extremely high. I thoroughly went through the carbs and they look great. I've adjusted the pilot screw AT 1.5 turns, 2.5 turns, and even 3 full turns. Doesn't make a difference either way. Looked for vacuum leaks by spraying starter fluid around the boots. Nothing changed. Rode the bike with the gas cap off to check with bad ventilation. Nothing changed. I even tried bypassing the air cut off valve and that made the bike run worse. Any suggestions would be helpful. Not sure if it's related but sometimes the turn signals work and sometimes they don't. Just wondering if there's some weird electrical thing going on here that might affect the idle. Thanks. Login or Register to Remove Ads Last edited by JGunn; 09-02-2018 at 05:00 PM.
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09-02-2018, 06:04 PM	#2
Vegas Street Rider Senior Member Join Date: May 2015 Location: Henderson, NV Posts: 1,108	I had erratic idle issues with my 2009 GZ. It turned out that the petcock diaphragm was bad. I rebuilt it and my idle issues stopped. Sometimes it would idle fine and other times it would idle normally and then gradually increase. Sometimes it would just die when I stopped. Regarding the turn signal problem, spray some electrical contact cleaner behind the switch and see if that takes care of it. Last edited by Vegas Street Rider; 09-02-2018 at 06:06 PM. Reason: Added additional info.
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09-02-2018, 06:40 PM	#3
JGunn Junior Member Join Date: Jun 2018 Posts: 18	I thought of that but even when I ride the bike on PRI I have an idle problem. PRI as you know bypasses the diaphragm and just let's the gas flow. I guess I'm a little curious why you need a petcock. Is it literally there to stop the gas in case you want to remove the tank. What's the great function of this valve that makes it necessary. Like I said I checked the flow of gas out of the petcock on PRI and it gushes out. I turned it on ON and sucked on the air valve to see if that works and it does. Login or Register to Remove Ads Last edited by JGunn; 09-02-2018 at 06:43 PM.
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09-02-2018, 09:54 PM	#4
Vegas Street Rider Senior Member Join Date: May 2015 Location: Henderson, NV Posts: 1,108	The petcock is designed to open and allow a given amount of fuel to the carburetor to provide the optimum air/fuel mixture based on the amount of vacuum the carburetor generates which is controlled by the throttle valve. If you leave the petcock on prime, the fuel to air ratio would be too high(rich). The diaphragm regulates that flow. Also, the petcock set on the ON position allows you to only run about 2.8 to 3 gallons of fuel out of the tank allowing you to have reserve fuel available when you make the switch to reserve so you are not left high and dry on the road. It does act as a shut-off as well on either the reserve or ON position as there is no vacuum pulling fuel out when the engine isn't running.
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