GY5 runs great.....dies, runs great..dies is this a bad CDI?

dieselhead · 08-17-2012, 12:04 AM

Hi folks, I put my 07 GY5 back on the road this week so my son can learn the ways of the road and ran into a very anoying problem. At any time running down the road, the bike just dies just like you turned the key off. If you imediately try to start it, absolutely nothing happens other than the engine spins over just fine but sounds like no spark. Wait about a minute or so, tap the starter and the bike fires right up like nothing bad ever happend! This happened 4 times on a 70 mile trip today, once in heavy 4 lane traffic :evil: I have a clean fuel tank, fuel filter and I cleaned the carb bowel out before this trip. When the bike runs, it runs perfectly without a single miss. The bike has under 1000 miles on it but its a 07. Band new battery. Wireing looks OK. Iv been away from this sight for a while but I figured you guys would have the mud on this issue
THANKS

SpudRider · 08-17-2012, 01:37 AM

If you've got good fuel flow, I think you're correct; the CDI unit is probably bad. :( I suggest you get a new CDI unit as soon as possible. The CDI units are inexpensive, and it's always good to have a spare handy.

Even if your current CDI unit is not bad, the spare CDI unit will greatly facilitate the troubleshooting of electrical problems.

Spud

Wild_Alaskan · 08-17-2012, 01:56 AM

A 400ex (quad) cdi will also work with your bike. I have a posh cdi and working stock one you can have if you would like

dieselhead · 08-18-2012, 01:45 AM

Quote:

Originally Posted by Wild_Alaskan

A 400ex (quad) cdi will also work with your bike. I have a posh cdi and working stock one you can have if you would like

Thanks for the offer, but Iv got a few dollars in my ebay account going towards a new one as I write this (THANKS SR).
The only other thing this problem "might be" is vacumm lock in the gas tank from a bad gas cap vent. It seems there is a very slight sucking sound when you pop the gas cap at times. Has anyone had a bad cap with this sort of problem?

SpudRider · 08-18-2012, 01:54 AM

Yes, I have heard of problems caused by bad gas cap vents, but I have never experienced this problem. All my current gas tanks are plastic.

I suggest you examine your gas cap to see if you can detect a problem. I also suggest you install the new CDI unit, and see if the problem disappears.

Spud

mike1346 · 08-19-2012, 01:35 AM

Quote:

Originally Posted by Wild_Alaskan

A 400ex (quad) cdi will also work with your bike. I have a posh cdi and working stock one you can have if you would like

Is this a more reliable CDI than a chinese brand? I think mine may have this issue now as I'm not getting spark :(

Wild_Alaskan · 08-19-2012, 01:47 AM

i used the posh cdi for about a year with zero problems, my old one was still working when I took it out. The posh gives a little more top end power, and the stock one will lug a little better in the low rpms, I don't have a extra 400ex (Japanese quad) CDI but they would probably be the best overall option. I do however have a trx300ex cdi that looks like it may be compatible. if you want all three of these you can have them for the cost of shipping if you start a thread contrasting them for others that may be interested :wink:

dieselhead · 08-19-2012, 11:38 AM

PM sent for the 400ex type posh unit. A bit more top end cant be a bad thing! THANKS

katoranger · 08-19-2012, 02:09 PM

I swapped an xr200r CDI for a china one. It worked too. Don't know about any performance benefits other than it ran.

humanbeing · 08-19-2012, 08:30 PM

Quote:

Originally Posted by katoranger

I swapped an xr200r CDI for a china one. It worked too. Don't know about any performance benefits other than it ran.

Don't know xr200r's "curve" , the "generic" chinese vertical's curve is like this: http://translate.google.com/translat....asp%3Fpid%3D6

dieselhead · 08-26-2012, 05:19 PM

Havent put in a new CDI yet but I think I may have found the problem. Time will tell. I took the gas cap apart and found the GY5 uses a very well sealed cap. It has a super tiny (like 1/32) hole under the twin latches to vent the tank. This tiny hole has a free ball bearing that sits over the top of it. the bearing, once a little wet makes a pretty good seal from any great amount of air entering the tank. Also the bearing is kept in place by a pressed in cap that has a hole in it but the cap shoulders block off the bearing cylinder side venting cuts. since a gasket covers the hole in the bearing cap, a side hole under the gasket is needed, but the pressed in cap blocks that vent cut in the cast housing. I worked the 1/32nd hole over with a slightly larger drill and craned it around to disrupt the bearing seat some what, then ground the bearing cap sides open to let air into the bearing cylinder. We have put on about 80 miles since the reworked gas cap and not a hickup. starts and keeps running.... we will see n i'll post if it conks out again.
THANKS for the ideas and help.

FastDoc · 08-26-2012, 10:51 PM

Good work. I have heard of gas caps causing problems.

SpudRider · 08-28-2012, 11:43 AM

Quote:

Originally Posted by FastDoc

Good work. I have heard of gas caps causing problems.

X2! I hope you found the solution.

Spud

Weldangrind · 08-28-2012, 11:45 AM

80 miles sounds like a good test. I'm guessing that you've solved it.

08-17-2012, 12:04 AM	#1
dieselhead Join Date: Jan 2008 Location: Catskill Mnts NY Posts: 85	GY5 runs great.....dies, runs great..dies is this a bad CDI? Hi folks, I put my 07 GY5 back on the road this week so my son can learn the ways of the road and ran into a very anoying problem. At any time running down the road, the bike just dies just like you turned the key off. If you imediately try to start it, absolutely nothing happens other than the engine spins over just fine but sounds like no spark. Wait about a minute or so, tap the starter and the bike fires right up like nothing bad ever happend! This happened 4 times on a 70 mile trip today, once in heavy 4 lane traffic :evil: I have a clean fuel tank, fuel filter and I cleaned the carb bowel out before this trip. When the bike runs, it runs perfectly without a single miss. The bike has under 1000 miles on it but its a 07. Band new battery. Wireing looks OK. Iv been away from this sight for a while but I figured you guys would have the mud on this issue THANKS __________________ 07 TMS200 GY-5 Zongshen 200 Dirt 03 BMW F650GS
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08-17-2012, 01:37 AM	#2
SpudRider Join Date: Jul 2008 Location: Idaho Posts: 25,054	If you've got good fuel flow, I think you're correct; the CDI unit is probably bad. :( I suggest you get a new CDI unit as soon as possible. The CDI units are inexpensive, and it's always good to have a spare handy. Even if your current CDI unit is not bad, the spare CDI unit will greatly facilitate the troubleshooting of electrical problems. 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
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08-17-2012, 01:56 AM	#3
Wild_Alaskan Join Date: Dec 2009 Location: Alaska Posts: 914	A 400ex (quad) cdi will also work with your bike. I have a posh cdi and working stock one you can have if you would like __________________ Dune buggy build http://chinariders.net/modules.php?n...wtopic&t=14470 400cc lifan build vid: http://youtu.be/20HoU8OK_Y0 other fun: http://tinyurl.com/wildalaskan
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08-18-2012, 01:54 AM	#5
SpudRider Join Date: Jul 2008 Location: Idaho Posts: 25,054	Yes, I have heard of problems caused by bad gas cap vents, but I have never experienced this problem. All my current gas tanks are plastic. I suggest you examine your gas cap to see if you can detect a problem. I also suggest you install the new CDI unit, and see if the problem disappears. 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

08-19-2012, 01:47 AM	#7
Wild_Alaskan Join Date: Dec 2009 Location: Alaska Posts: 914	i used the posh cdi for about a year with zero problems, my old one was still working when I took it out. The posh gives a little more top end power, and the stock one will lug a little better in the low rpms, I don't have a extra 400ex (Japanese quad) CDI but they would probably be the best overall option. I do however have a trx300ex cdi that looks like it may be compatible. if you want all three of these you can have them for the cost of shipping if you start a thread contrasting them for others that may be interested :wink: __________________ Dune buggy build http://chinariders.net/modules.php?n...wtopic&t=14470 400cc lifan build vid: http://youtu.be/20HoU8OK_Y0 other fun: http://tinyurl.com/wildalaskan
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08-19-2012, 11:38 AM	#8
dieselhead Join Date: Jan 2008 Location: Catskill Mnts NY Posts: 85	PM sent for the 400ex type posh unit. A bit more top end cant be a bad thing! THANKS __________________ 07 TMS200 GY-5 Zongshen 200 Dirt 03 BMW F650GS
	0

08-19-2012, 02:09 PM	#9
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	I swapped an xr200r CDI for a china one. It worked too. Don't know about any performance benefits other than it ran. __________________ You meet the nicest people on a Honda Clone.
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08-26-2012, 05:19 PM	#11
dieselhead Join Date: Jan 2008 Location: Catskill Mnts NY Posts: 85	Havent put in a new CDI yet but I think I may have found the problem. Time will tell. I took the gas cap apart and found the GY5 uses a very well sealed cap. It has a super tiny (like 1/32) hole under the twin latches to vent the tank. This tiny hole has a free ball bearing that sits over the top of it. the bearing, once a little wet makes a pretty good seal from any great amount of air entering the tank. Also the bearing is kept in place by a pressed in cap that has a hole in it but the cap shoulders block off the bearing cylinder side venting cuts. since a gasket covers the hole in the bearing cap, a side hole under the gasket is needed, but the pressed in cap blocks that vent cut in the cast housing. I worked the 1/32nd hole over with a slightly larger drill and craned it around to disrupt the bearing seat some what, then ground the bearing cap sides open to let air into the bearing cylinder. We have put on about 80 miles since the reworked gas cap and not a hickup. starts and keeps running.... we will see n i'll post if it conks out again. THANKS for the ideas and help. __________________ 07 TMS200 GY-5 Zongshen 200 Dirt 03 BMW F650GS
	0

08-26-2012, 10:51 PM	#12
FastDoc Join Date: Mar 2009 Location: Southeastern Washington desert Posts: 14,761	Good work. I have heard of gas caps causing problems. __________________ Happy to serve.
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08-28-2012, 11:45 AM	#14
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	80 miles sounds like a good test. I'm guessing that you've solved it. __________________ 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
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