GZ 125 no spark

robg123 · 08-13-2016, 06:06 PM

I have a 03 k3 gz125 with no spark,had been sitting -the guy took a vid of it eing jumped and firing up then sold it on.i have painted it ,cleaned carbs ,changed ignition,and now going to start it found no spark..
i have hard wired the clutch and side stand switches,cleaned coil terminals.next check is the side stand switch relay i guess.. does the yellow black wire ground to stop the engine?

robg123 · 08-14-2016, 06:45 AM

just got myself a spark tester and have noticed with ignition on ,and me flicking kill switch on/off the sparkplug tester flashes when kill switch set to 'run' but no spark when i turn it over..

alantf · 08-14-2016, 11:14 AM

First of all try spraying the kill switch with aerosol contact cleaner. Second...you say that the previous owner got it to fire when he jumped it. If it started with another battery, I can only suppose your battery has a problem. Have you tested it? If not, charge it for 5 or 10 hours at 0.75amps (certainly no more than 2amps), disconnect the charger, leave the battery sitting for half an hour, then test the battery voltage with a meter, and let us know the results. Bad battery is one of the most common faults of the GZ.

wacio · 08-14-2016, 10:34 PM

Test components from the easiest to test ending with ignition module. Verify if your run switch is in run position than:
1. Fuse
2. Battery
3. Safety switches (clutch, stand, ignition switch)
3. Spark plug - try another one to see if yours is dead.
4. spark plug wire and coil - resistance - primary 3-5 ohm, secondary 17k-28k ohm
inspect spark plug wire for damage (could be melted if too close to head)
5. Pickup coil (crankshaft) - Resistance 400-650 ohm and voltage more than 5V (while cranking)
6. Ignitor - measure using multimeter per manual (I have one for GZ250 - not sure if your use same module)
Be patient - you'll get there

robg123 · 08-15-2016, 03:04 AM

ok great stuff guys ill get the multimeter out.i have fitted new battery ,ignition key has been changed but i also have a spare plug with the wires chopper and twisted (as per haynes diagram so i know all is good .the kill switch also is on the starter circuit so i dont think its that as it spins over in on and doesnt when switch is off,i do have power at both coil wires when ignition is on.will try test coil and igniter today

robg123 · 08-15-2016, 04:49 AM

coil 5.2ohm and 23k so seems within spec i guess

robg123 · 08-15-2016, 07:21 AM

so i have hard wired clutch,neutral,sidestand switches to guarantee continuity,
side stand relay checked out ok ,
coil seemed within tolerances - the coil wires couldnt be the wrong way round could they?
checked r/h switchgear ,stop switch/started all working as they should.
it has brand new battery showing good charge.
tried different spark plugs
My haynes book only shows the ignitor test with a different model (gs125) where the pickup wires are on a seperate plug to the rest of the wires so can be unplugged and check for spark.. could i do the test with the cdi box plugged in and just probe wires?
getting frustrating.haha

robg123 · 08-15-2016, 07:45 AM

https://1drv.ms/i/s!ApmwTPXyzTtBnwQdp_sYoN1rQenC wiring diagram

wacio · 08-15-2016, 09:46 AM

On your diagram the pickup coil is shown as part of the alternator - connected to the ground (black/white wire) and blue wire going to igniter. There should be connector (shown on diagram - two conductors) somewhere close to engine - probably under the tank. You can disconnect and check resistance there (between blue and black/white on cable going to engine) .

robg123 · 08-15-2016, 04:27 PM

with the multimeter set to 2000 i was getting 245 ohm ..

08-13-2016, 06:06 PM	#1
robg123 Junior Member Join Date: Aug 2016 Posts: 16	GZ 125 no spark I have a 03 k3 gz125 with no spark,had been sitting -the guy took a vid of it eing jumped and firing up then sold it on.i have painted it ,cleaned carbs ,changed ignition,and now going to start it found no spark.. i have hard wired the clutch and side stand switches,cleaned coil terminals.next check is the side stand switch relay i guess.. does the yellow black wire ground to stop the engine? Login or Register to Remove Ads
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08-14-2016, 11:14 AM	#3
alantf Senior Member Join Date: Nov 2008 Location: Tenerife (Spain) Posts: 3,715	First of all try spraying the kill switch with aerosol contact cleaner. Second...you say that the previous owner got it to fire when he jumped it. If it started with another battery, I can only suppose your battery has a problem. Have you tested it? If not, charge it for 5 or 10 hours at 0.75amps (certainly no more than 2amps), disconnect the charger, leave the battery sitting for half an hour, then test the battery voltage with a meter, and let us know the results. Bad battery is one of the most common faults of the GZ. __________________ By birth an Englishman, by the grace of God a Yorkshireman. Login or Register to Remove Ads
	0

08-15-2016, 03:04 AM	#5
robg123 Junior Member Join Date: Aug 2016 Posts: 16	ok great stuff guys ill get the multimeter out.i have fitted new battery ,ignition key has been changed but i also have a spare plug with the wires chopper and twisted (as per haynes diagram so i know all is good .the kill switch also is on the starter circuit so i dont think its that as it spins over in on and doesnt when switch is off,i do have power at both coil wires when ignition is on.will try test coil and igniter today Login or Register to Remove Ads
	0

08-15-2016, 09:46 AM	#9
wacio Senior Member Join Date: Apr 2016 Location: Illinois Posts: 174	On your diagram the pickup coil is shown as part of the alternator - connected to the ground (black/white wire) and blue wire going to igniter. There should be connector (shown on diagram - two conductors) somewhere close to engine - probably under the tank. You can disconnect and check resistance there (between blue and black/white on cable going to engine) . Last edited by wacio; 08-15-2016 at 09:48 AM.
	1

08-14-2016, 06:45 AM	#2
robg123 Junior Member Join Date: Aug 2016 Posts: 16	just got myself a spark tester and have noticed with ignition on ,and me flicking kill switch on/off the sparkplug tester flashes when kill switch set to 'run' but no spark when i turn it over..
	0

08-14-2016, 10:34 PM	#4
wacio Senior Member Join Date: Apr 2016 Location: Illinois Posts: 174	Test components from the easiest to test ending with ignition module. Verify if your run switch is in run position than: 1. Fuse 2. Battery 3. Safety switches (clutch, stand, ignition switch) 3. Spark plug - try another one to see if yours is dead. 4. spark plug wire and coil - resistance - primary 3-5 ohm, secondary 17k-28k ohm inspect spark plug wire for damage (could be melted if too close to head) 5. Pickup coil (crankshaft) - Resistance 400-650 ohm and voltage more than 5V (while cranking) 6. Ignitor - measure using multimeter per manual (I have one for GZ250 - not sure if your use same module) Be patient - you'll get there
	0

08-15-2016, 04:49 AM	#6
robg123 Junior Member Join Date: Aug 2016 Posts: 16	coil 5.2ohm and 23k so seems within spec i guess
	0

08-15-2016, 07:21 AM	#7
robg123 Junior Member Join Date: Aug 2016 Posts: 16	so i have hard wired clutch,neutral,sidestand switches to guarantee continuity, side stand relay checked out ok , coil seemed within tolerances - the coil wires couldnt be the wrong way round could they? checked r/h switchgear ,stop switch/started all working as they should. it has brand new battery showing good charge. tried different spark plugs My haynes book only shows the ignitor test with a different model (gs125) where the pickup wires are on a seperate plug to the rest of the wires so can be unplugged and check for spark.. could i do the test with the cdi box plugged in and just probe wires? getting frustrating.haha
	0

08-15-2016, 07:45 AM	#8
robg123 Junior Member Join Date: Aug 2016 Posts: 16	https://1drv.ms/i/s!ApmwTPXyzTtBnwQdp_sYoN1rQenC wiring diagram
	0

08-15-2016, 04:27 PM	#10
robg123 Junior Member Join Date: Aug 2016 Posts: 16	with the multimeter set to 2000 i was getting 245 ohm ..
	0