gy6 no spark nightmare (backyard) By case (Read 25,399 times)

[case]

I got this scooter as my first one. I know something about engines, I am a backyard mechanic without high tech tools. It was not running and had been sitting for some time. After some bypassing of switches, handlebar, killswitch, and some creative wiring it got power and no spark. After some time of messing with it and changing out plugs, I got a gsxr plug to fire on the head with a fat blue spark. I immediatly put the plug in and it fired....I was so happy I took it for a ride...it was doing 60 and it was raining hard. I went thru a few puddles doing 40 and it was still running when i got back. The next day, no spark. checked all connectors and blew them out and sparyed down with wd-40..still no spark. pulled stator cover to inspect for water/looks pretty clean without pulling flywheel. Dont have a multi meter at the house. Cant tell if stator is wet or shorted..clipped b/w wire to cdi, hotwired ignition, will check grounds tomorrow and run new ground from cdi to frame.
please help me get some spark fellas!!
How long would it take to "dry out?
can i hold the wires that goto the coil and bump the starter to see if there is current?
should i run all new grounds?
or let it dry for a week?
or light in on fire>

Attachments:

[Alleyoop]

No I would not hold the wires going to the CDI it delivers about 400V. Just go to the hardware store and pick up a multi meter they are cheap under $10.00 or less, also pick up a 12v LIGHTER TESTER they are INVALUABLE to test if a wire has current or not. Just ground the wire on it and PROBE the wire you want to check if it lights you have juice.

But as you know SCOOTERS, MOTORCYCLE ELECTRICS do not like water AT ALL.
So either something shorted out or it is shorting out.

Now SPARK is PLUG, BOOT CAP, COIL, CDI, PICKUP COIL and STATOR and proper ground of course.
Alleyoop

[case]

Thanks Alley oop, you posts are like gold and Im sure there are a bunch of scooter owners that owe you one on here, me inluded
thanks
I will get a multi-meter today, I had one but my tools got stolen a while ago, I work as a scooter tech helper, so this is embarrasing but challenging to me, as my experience with electrics has some background but not enough. I am hoping with a meter and runing some new grounds that it will fire. It doesnt seem likely to me the cdi or coil or stator, it had intermitttent spark, so if it is one of those 3 im thinking cdi.
it will be a challenge...I plan to start my own emergency scooter business after selling my van .
So what is the general concensus? Is the main theory that the bike is not grounded, or does it sound like cdi or stator?
I guess i will see later when I follow the flow chart to narrow it down with the meter...(money is tight sometimes)
thanks and i wont ever ride a scooter in the rain again

[case]

Some questions as before i goto the store or scooter parts place.
I ran a jumper ground from cdi no dice. Then i realized i had a scooter to try out my "fried" stuff on.....first i tried my plug cap and boot on the 50cc....fat blue spark. (eliminated) Then i tried my cdi and the 50 had no spark. Then I replaced the stock cdi on the 50 and spark again....will the 150cc cdi fire on a 50cc bike?
I am just grounding the plug to the head to check,not firing it.
If a 150cc cdi will fire a plug on a 50 then my cdi is burnt and i need to go get a new one.
Thanks!!!!
Plug, boot and cap eliminated
cdi may be toast, wwas replced before and zip tied to the wrong area where i feel it got really wet.
what are your thoughts

[case]

::)Well i got some toys and some interesting readings, I have 12v coming out of the cdi (black wire) I have no reading at the coil when starting or still. The orange wires from the stator read 2
and there is no voltage from the pickup coil at all?
safe to say it is the pickupcoil?
I have one but dont want to cut unless its true
thanks

Attachments:

[Alleyoop]

Here you go how to find out WHY NO SPARK.
Alleyoop


www.scooterdoc.proboards.com/index.cgi?board=electrical&action=display&thread=4334

[case]

Awesome post. I dont have the meter set correctly i think, but I am getting power flow from the stator and also the pickup is reading as well. Glad i didnt cut it off. I willswap my coil next, i have one but it has twp prongs...mine has one and a gound that goes to a bolt next to it.
Im pretty sure its the cdi at this point but im pretty sure the stator and pickup arent shorted
Thanks Alley i feel like im geting closer to chasin it down

[Deleted]

I had this problem with my Roketa once. Turned out to be loose spade clips on the power wires to the coil.

[case]

Thanks and yes I have checked every connection. Today I pulled all the grounds and polished them with sandpaper, they were black and cruddy withwd-40 and water and grime....cleaned it all up, ordered a race cdi, (wanted one anyway) ran a permanent jumper from the cdi to the frame and cleaned the pickup coil magnet of rust and residue. When the new cdi arrives, I will run another ground from the negative terminal of the batt to the green prong on the coil and back to the frame.
If none of this works its the coil, need a performance one anyway..stipped off all the gauges and top plastic for a euro look, feels less clunky and cleaner.
crossing fingers
thanks for all the help

[Bashan]

If you have a black wire going into the CDI that reads 12v DC you have a DC system. Here is how you differentiate between a DC CDI and an AC:

Also, a DC system has a different stator, it does not have a R/B wire that carries AC to the CDI. The DC CDI gets it's juice from the battery, not the stator. So be aware of those things when ordering parts and testing.

I ran across a diagram of the spark genesis that Alley went over, maybe it will help clarify things. This is for an AC SYSTEM:

For a DC system swap the R/B for a black 12v DC wire from the ignition.

You asked about testing the feed to the coil. A lot of guys say you can't test it because it is intermittent bursts of electricity. I disagree. I've tested many a CDI for juice to the coil and found several bad CDIs. For an AC system I found a way to check the CDI output to the coil. Set your multi to AC and unhook the positive wire to the coil. Put the red probe into the connector on this wire (we're testing in series) and ground the other test probe to the green coil terminal or the frame. Make sure the kill switch is off (it grounds the coil), turn on the key, and crank the engine. I find you should get about 15 to 40v AC.

Make sure your multi can handle the juice running through it but my little one does, my big one sure as hell would. I've never tested a DC system so I'm not sure how that would shake out. Without knowing what values you should get you would at least be able to tell if anything is coming out of the CDI. I'd try setting the multi to AC and DC and see what happens.

You can also ohm out a coil:

[case]

Thanks man. I am really confused, as i cant figure this out. The replacement cdi's for this gy6 fit any chinese model 50cc to 150cc.
The web says that this italica model is AC fired but the black wire coming from the cdi says otherwise like you noted.
However, a dc system will not run without the battery and mine runs real well with no battery (when running) .....So, is it a combo ac/dc system? instead of a red wire from the stator I have a green one, this is not like most wiring diagrams for the gy6
im stumped.
If it will run without a battery it is AC right?
can i run a coil and cdi designed for GY6 150CC engine or this some kind of exception to the 150cc cdi coil rule?
I also noted that my coil looks different without 2 prongs
arrrg
I hope with persistence i can figure this out and with your help
thanks again

[case]

I took some pics to help you guys see what im seeing.
please review and post your thoughts.

stock? cdi and test coil from another gy6/its different
what the heck? i have a 5 gallon gas can ready to douse this thing!!

[case]

I found this on the net
Here is a standard ignition circuit for a chinese scooter. Note that the red wire from the stator to the CDI will not be on a DC fired system. The kill switch wire will instead be the positive power source from the igntion key switch.

So, i guess if my killswitch has been disabled, power to the cdi is disabled. my kill switch is disabled.

What doesnt make sense to me, is that it runs without a battery
i guess this 150 has a combination ac/dc system

[case]

The kilswitch has to be " working" to supply power to the cdi.
This entire time i have been trying to fire it with the killswitch bypassed and not completing the circuit. I guess the killswitch went bad after the rain and i bypassed it at that point along time ago.
now i must go back and make it work to make the cdi get power.
gettting real close now, nothing may be wrong with any part..
back the drawing board

[Deleted]

From the looks of the CDI plugs you have a DC CDI. The black wire in the 2 terminal plug should be 12v DC with the key on. The other wires go to the coil and ground. Does the wire you cut go to the pickup coil?