Kymco S125 no spark By jomama (Read 11,761 times)

[jomama]

Hi lads, I am the new kid on the block here with a question. My 08 Kymco peoples S125 became increasingly inconsistant when starting. Thought it was high humidity. Put it in a heated garage and nothing changed. Spark one minute, none the next. Now there is none. I have a CD on the testing procedure for the cdi but using a quality Fluke meter I consistantly get readings that do not match up with the chart. Now the instructions state " due to a semiconductor in the circut, a sanwa or kowa tester must be used" . In addition the chart is pretty confusing. Is there anyone here that is familiar with this procedure. Thanks for any help this is driving me nuts now for weeks.

[Bashan]

CDIs are low on my list for suspects causing spark problems. Does your plug boot and coil wire look good? Then I'd check the voltage coming from the pick up coil and the power wire to the CDI and make sure they're up to spec. Does your CD show how to perform those tests?
Rich

[sprocket]

Check the ground from the engine case to the frame.. it is often overlooked....

[jomama]

MY cd gives tersting process but specifies a specific brand tester because of a semiconductor in the unit so that put a halt to that. I went to the elect section and looked into testing the out from the stator but the wiring description dosent match up. My unit has only 3 wires from it. 2 attached to a plug (pink & Yello ) and a 3rd which is blue w/yel tracer which is attached to a seperate bullet type connection and with this arrangement i cannot perform the test for stator output. Another curious thing is where the 2 cdi units are explained (AC/DC) it shows the AC as having 2 plugs (#1 with either 3 or 4 wires ) and #2 as having 2 wires . The DC is described as having #1 3 or 4 wires but #2 as having 1 wire. Now mine is as described by the AC setup but the Monsterscooterparts website states Kymcos are DC . The repair CD I have dosen't even list a color code sheet or a wiring diagram which would be real nice. I am about to give up.

[sprocket]

Where does the power spark wire for the CDI come from? The stator directly or the rectifier/regulator or battery?

Stator direct and it is AC- CDI...somewhere else likely DC

Check your engine ground and spark plug boot, ignition coil wires etc...

[jomama]

The power wire to the cdi comes from the regulator. Sooo i guess its DC . Heres another quirk in this mess, the cdi has the 6 prong (4&2) plug on it but also has a seperate single wire that connects to another unit mougetting nted along side that looks like a smaller version . I mean AC/DC or whatever the testing procedure for the stator output should be the same and I cant do it because I only have 3 wires from it and that dosent correspond with the testing procedure listed .I am truly baffled. Its getting pretty old now and after repeatedly checking every connection, checking grounds, coil, plug etc then i find I need a "special meter" for cdi testing and the stator test is a no no either and I cant check them and they arent exactly cheap. Its got to be one ot the other. Oh yeah I checked the kill switch too.

[tvnacman]

check the grounds with some load , use a pigtail with a 40 or 60 watt bulb . put one lead to the pos battery and ground the other end to the engine and frame . If the ground is weak the bulb will not light .

next on the CDI on the two pin plug are one of the wires black with white tracer ? Put your meter in DCV positive battery put the other probe on the kill wire unpluged from the cdi , with the key off you should read battery voltage , with the key on you should get about 0VDC.
Also read the voltage across the fuse both key on and off tell me what you get .

scooterdoc.proboards.com/index.cgi?board=electrical&action=display&thread=4997

John

[Kaveman]

Bad stator assy ?
will

[jomama]

Here is what i tried today, Tested the puls coil and got a reading of 105.5 reading should be bet 70 & 130 so ok there. The puls coil wire goes to cdi as power in i would guess and a wire comes out to the coil. When I check the primary side of coil i get no voltage. Shold read 12vlts. After testing things and replugging everything back,, I shorted a plug to the head and had great spark. Then I put the plug wire on the plug in the engine expecting an instant start. NOTHING. Undid the plug wire and went to the plug grounded to head and NO SPARK AGAIN. The Ohms readings on the coil are well within specs. Primary and secondary w& without plug wire attached. I am thinking if the cdi is wacky, could I hook a hot wire from the bat to the coil and get my 12 vlts there an see if it starts. If it does then it tells me there is no power from the cdi to the coil. But i am concerned with burning something out . Now like i said no voltage to coil either just with the ign switch on or when its on and cranking the engine. I remember that when it was running a while back I checked the alternator output and at the bat terninals i was getting 14+ vlts so I am sure the alt is OK. I also checked the engine to frame and its Good as gold.

[jomama]

Possessed is the term that applies here. This afternoon after i wrote the above replly, i hooked up all connections and hit the starter and it started right up and ran fine after warm up. So i sez to meself, heres my chance to check the voltage going to the coil. While pulling back the little rubber boot on the primary terminal from the CDI, i disconnected the wire. No problem re connect and start it up again to check voltage. NO WAY. It would not start. NO SPARK . So then i put the ohm meter on beep and checked the wire from the cdi to the coil and got continuity there. Then while still connected to the coil end of the wire i grounded to the frame and also got a beep which would lead me to believe its grounding somewhere between the cdi and the coil. Now mind you this wire was not connected to either the coil ot the cdi when I made this last test just a test from the coil end to a ground . GO FIGURE . I have to recheck the schematic but i dont believe t passes through the kill switch. I may be wrong. By the way when it was running i purposely hit the kill switch and it does indeed work . When i returned it to the run position just prior to my check for voltage and disconecting the wire it restarted.

[sprocket]

Halloween gremlins?

[Kaveman]

That or he really needs an exorcist asap !

[jomama]

Back again with a humble report. I went out and rechecked the wire from the coil to cdi and end to end continuity ok there. Tried each end to ground and no beep so i must have been hearing things. The wire from the puls coil which i tested earlier for ohms and showed ok was checked for continuity to cdi and its good also. So i dont have spark or voltage at the coil . The voltage is going in to the cdi but not out to the primary side of the coil. I am remembering fondly a Harley Davidson Topper scooter i had. Soooooo simple . Give me point ign any day.

[sprocket]

You should measure the voltage on the pick-up coil coming from the stator.. it should be above .5 volts AC

It could simple be a bad pick-up coil and the CDI never gets a message to fire... they also go weird like you have had.. works sometimes then not work

[jomama]

Sprocket, when you say the pickup coil are you refering to what is called the PULSER COIL on this unit ?. It sends the pulses to the CDI so i guess it would be the same thing. Right? .