hesitation and back fires

weiser23 · 06-18-2011, 08:34 PM

when down shifting my bike seems to be back firing alot more and when when you get back on the throttle it hesitates , if completely stopped sometimes it stalls. I was coming to a stop sign almost stopped and starting to turn i hit the throttle the engine stalled and the bike hit the ground and I was scrambling to get the bike back up before anyone saw ;three week ago I had a new spark plug air cleaner and what ever the first service gets

FastDoc · 06-18-2011, 11:32 PM

Glad you and the bike are OK.

Please remind us. You ride a Q? What modifications if any?

SpudRider · 06-19-2011, 12:04 AM

Quote:

Originally Posted by FastDoc

Glad you and the bike are OK.

Please remind us. You ride a Q? What modifications if any?

X2 on all points.

Spud

weiser23 · 06-19-2011, 04:59 AM

09 qlink stock, when I say back fire I dont mean not real loud just popping most of the time, but under bridges its pretty loud

SpudRider · 06-19-2011, 12:06 PM

Perhaps the main jet in your carburetor is too rich. At what elevation are your riding, and what is the size of your current main jet?

Spud

weiser23 · 06-20-2011, 03:05 PM

Quote:

Originally Posted by SpudRider

Perhaps the main jet in your carburetor is too rich. At what elevation are your riding, and what is the size of your current main jet?

Spud

im not sure what ever the stock bike has on it

FastDoc · 06-20-2011, 03:34 PM

I don't recall a misjetted, much less rich Q ever in factory configuration. Plugged air filter maybe?

Weldangrind · 06-21-2011, 01:15 AM

Maybe the reed valve in the smog device (if equipped) isn't seating. That would allow too much oxygen to hit the exhaust.

weiser23 · 06-21-2011, 07:46 AM

[quote="Weldangrind"]Maybe the reed valve in the smog device (if equipped) isn't seating. That would allow too much oxygen to hit the exhaust.[/quo

thanks for the tip what can i do about that

Weldangrind · 06-21-2011, 10:21 AM

Toss it in the trash and make a block-off plate, unless you live in the PRK. If your municipality or State requires that you keep such a ridiculous device, then get crafty about disabling it.

Once removed, the catalytic converter could be removed as well.

martin556310 · 06-21-2011, 02:22 PM

My bike was cutting out and misfiring in the high gears and would random stall at stops. I replaced the CDI box (under the seat) and it fixed it. The part was cheap, but make sure you get the correct connector type.

SpudRider · 06-21-2011, 03:08 PM

Quote:

Originally Posted by martin556310

My bike was cutting out and misfiring in the high gears and would random stall at stops. I replaced the CDI box (under the seat) and it fixed it. The part was cheap, but make sure you get the correct connector type.

I agree.

These symptoms might also indicate a bad CDI unit. It's always a good idea to have a spare CDI unit on hand. The spare CDI unit greatly facilitates the troubleshooting of electrical problems. Also, if your CDI unit fails, you can plug in the spare, and go riding, rather than wait for a new one to arrive.

Spud

Weldangrind · 06-21-2011, 10:44 PM

I agree that a bad CDI can cause misfiring, but this symptom is more likened to back-firing, if I'm understanding correctly. My leading theory is still that it's an air / fuel issue, however it's caused.

SpudRider · 06-22-2011, 01:26 AM

Quote:

Originally Posted by Weldangrind

I agree that a bad CDI can cause misfiring, but this symptom is more likened to back-firing, if I'm understanding correctly. My leading theory is still that it's an air / fuel issue, however it's caused.

I agree.

The cause is most likely an air/fuel issue. However, it's always a good idea to have a spare CDI unit handy. For example, in this particular instance, substituting the CDI unit could help rule out electrical problems as a contributing factor.

Spud

bigheavy150 · 06-29-2011, 11:13 AM

Idle jet can be lean. These bikes dont have accelerator pumps to give that extra shot of gas when you open throttle quickly.This leaves you with a 1/10th second of very lean mixture. not a problem if its correct to begin with but your idleing with a hot motor and you jump on the gas giving the motor a big gulp of fresh air but still that tiny idle jet of fuel, then the fuel begins to get sucked out the jets like its supposed to.

We are dealing with really tiny motors, they can be real picky about carburation...

check your idle screw settings.maybe go 1/2-3/4 turn out. what altitude are you at?

06-18-2011, 08:34 PM	#1
weiser23 Join Date: Jan 2011 Location: mechanicsburg pa Posts: 166	hesitation and back fires when down shifting my bike seems to be back firing alot more and when when you get back on the throttle it hesitates , if completely stopped sometimes it stalls. I was coming to a stop sign almost stopped and starting to turn i hit the throttle the engine stalled and the bike hit the ground and I was scrambling to get the bike back up before anyone saw ;three week ago I had a new spark plug air cleaner and what ever the first service gets
	0

06-18-2011, 11:32 PM	#2
FastDoc Join Date: Mar 2009 Location: Southeastern Washington desert Posts: 14,761	Glad you and the bike are OK. Please remind us. You ride a Q? What modifications if any? __________________ Happy to serve.
	0

06-19-2011, 12:06 PM	#5
SpudRider Join Date: Jul 2008 Location: Idaho Posts: 25,054	Perhaps the main jet in your carburetor is too rich. At what elevation are your riding, and what is the size of your current main jet? Spud __________________ Spud "Never argue with an idiot. He will drag you down to his level, and beat you with experience." Mark Twain 2015 Zongshen ZS250GY-3 (RX3) 2006 Zongshen ZS200GY-2 (Sierra 200) 2005 Honda XR650L 2004 Honda CRF250X 1998 Kawasaki KDX220 Mods made to my Zongshen ZS200GY-2: http://www.chinariders.net/showthread.php?t=6894
	0

06-20-2011, 03:34 PM	#7
FastDoc Join Date: Mar 2009 Location: Southeastern Washington desert Posts: 14,761	I don't recall a misjetted, much less rich Q ever in factory configuration. Plugged air filter maybe? __________________ Happy to serve.
	0

06-21-2011, 01:15 AM	#8
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Maybe the reed valve in the smog device (if equipped) isn't seating. That would allow too much oxygen to hit the exhaust. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

06-19-2011, 04:59 AM	#4
weiser23 Join Date: Jan 2011 Location: mechanicsburg pa Posts: 166	09 qlink stock, when I say back fire I dont mean not real loud just popping most of the time, but under bridges its pretty loud
	0

06-21-2011, 07:46 AM	#9
weiser23 Join Date: Jan 2011 Location: mechanicsburg pa Posts: 166	[quote="Weldangrind"]Maybe the reed valve in the smog device (if equipped) isn't seating. That would allow too much oxygen to hit the exhaust.[/quo thanks for the tip what can i do about that
	0

06-21-2011, 10:21 AM	#10
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Toss it in the trash and make a block-off plate, unless you live in the PRK. If your municipality or State requires that you keep such a ridiculous device, then get crafty about disabling it. Once removed, the catalytic converter could be removed as well. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

06-21-2011, 02:22 PM	#11
martin556310 Join Date: May 2011 Location: Michigan Posts: 2	Replacing the CDI fixed mine My bike was cutting out and misfiring in the high gears and would random stall at stops. I replaced the CDI box (under the seat) and it fixed it. The part was cheap, but make sure you get the correct connector type.
	0

06-21-2011, 10:44 PM	#13
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	I agree that a bad CDI can cause misfiring, but this symptom is more likened to back-firing, if I'm understanding correctly. My leading theory is still that it's an air / fuel issue, however it's caused. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

06-29-2011, 11:13 AM	#15
bigheavy150 Join Date: Jan 2011 Posts: 119	Idle jet can be lean. These bikes dont have accelerator pumps to give that extra shot of gas when you open throttle quickly.This leaves you with a 1/10th second of very lean mixture. not a problem if its correct to begin with but your idleing with a hot motor and you jump on the gas giving the motor a big gulp of fresh air but still that tiny idle jet of fuel, then the fuel begins to get sucked out the jets like its supposed to. We are dealing with really tiny motors, they can be real picky about carburation... check your idle screw settings.maybe go 1/2-3/4 turn out. what altitude are you at?
	0