Taishian 125cc

[Macrofeet]

As most of you know i got a 125 i've been trying to fix up well i have reached the end of my ideas for trying to get the thing to work so i am looking for some help

The problem is i cannot get a spark from the damn thing the starter moter turns over but no spark

please see the following

These parts are working 100% sure

Spark plug
Cdi
Ht lead
Battery
Starter moter
Ignition switch

Here is what parts i have replaced

Voltage regulator
Magneto mag and pulse coil

here is what i have checked

Ignition switch to the cdi the wire is okay

the wire from the pulse coil to the cdi is good

the wire from the ignition coil to the cdi is good and so is the other wire

any hlep would be gr8

[oldperson]

You don't mention the engine kill switch circuit which I think consists of the kill switch, side stand and ign switch. It operates by grounding the the black/white wire from the cdi so the best way to discount this circuit is to disconnect the black/white wire at the cdi. The battery, rectifier etc have no effect on the the ignition circuit for the purpose of the spark so forget about anything 12volts including the brake switch indeed these bikes will start on the kickstart with the battery removed from the bike!(with the ign switch on).If it is not the kill circuit you preventing it starting you need a multimeter to check further as you need to check continuity in the magneto and pulse coil + the AC voltages produced by them.

[BillyGreen1973]

The ignition coil its self could be duff.

[Macrofeet]

Thanks for th quick replys

i've replaced the coil as the black connection was slightly worn
i tested the new and old on my 50cc with the spark plug and it fired up fine i also checked with a multimeter it was as it should be

i tested the green wire this is fine and also the black wire is fine to the cdi

Magneto

the story i got with the bike was

The bike was dropped on its side it worked for a bit afterwards apparently but then died

it must have been dropped quite heavy maybe off a cliff lol kidding the exhaust was damaged and hanging off when i got it and there was deep scratches on the side front pannel

i was thinking that the magnetism could have been damaged from the impact of this fall

i cleaned it all up as everything was rusted and water damaged from being left out in winter and replaced the parts which were rusty or non working or damaged

the parts i replaced included the pulse coil and the magneto as the pulse coil was rusted

i did not replace the flywheel its self which was rusted on the inside connection pannels and the raised square was also rusted which i cleaned with wd40 along with the inside pannels

i read in the 50cc manual about testing the restance for the pulse coil/trigering coil had a quick look at this but then i replaced with new assuming it should be working, havent tested yet i think that will be my next step

could anyone tell me what should the gap be under the pulse coil to the squre on the fly wheel i am wondering if this has become to large when i removed the rust of it?

thank you for the idea about the cut of switch did not think of this what so ever will try dissconnecting this next

[oldperson]

the gap is fixed by the mounting so if the new pulse coil is the same size the gap should be ok. You can test this with your meter as follows set the meter to AC volts on a low scale, it's only about .75 volts at idle disconnect the cdi and connect one lead to the Blue/Yel wire and the other lead to a good earthon the engine. Then rotate the magneto as the raised bit passes the coil there should be a sort of reading (the digits should change) the reading will be meaningless and can be ignored you just need to see it fluctuate. If it does it's probably ok.

[Macrofeet]

thanks alot will try this also have some karma

[Macrofeet]

Just tried this and was getting on 200 ac

0.01

should it be higher then this ?

[oldperson]

probably, anything shows its working try it on somthing like 10vdc scale if you unscew it you can just pass it over the magnet by hand, one I have shows somthing at about one inch from the coil.

[oldperson]

sorry that should have said probably not. If 200ac is the smallest scale the meter will probably not display it properly. So try a small DC range as I said the value is unimportant it is seeng a fluctuation as the magnet passes the coil. Unless your meter has peak hold or glitch etc you will not get a reading and if you did you would have no idea whether it was correct or not. The coil I have has a resistance of 132 ohms (blue/yel and mounting) so if yours is similar and you get a fluctuation it should be Ok

[Macrofeet]

tried it on me 50 cc and it was comming up 0.01 when it passed the same, i will try again tomorrow on another setting

Took the black/white wire out of cdi but have not be able to test as the kick start is missing and the battery went flat before i could test properly

have to test when its charged up tomorrow

[oldperson]

To test the kill circuit set meter to audible continuity and connect one lead to the black/white and the other to engine/frame and it should beep(continuity) turn the ignition to on and the beep should stop keeping the ignition switch on turn the kill switch and it should beep turn it back to stop beep and then put the side stand on and it should again beep, raise the side stand and it should stop. The ignition/kill circuits work by earthing the cdi via the black/white wire so this wire must be open circuit (no contnuity to earth) for the engine to run. This wire should not be touched when the engine is running as it has about 100vac on it and may make you jump about!