Chinese 250cc no spark
#1
Chinese 250cc no spark
Hello I recently bought a Chinese 250cc with a GN300 it had spark when I bought it and go figure brought it home to clean the carb and now I have no spark (tested by connecting spark plug to the block) it is a DC system which I have power at both prongs of my ignition coil and even have battery power at my spark plug. Where do I go from here ? Also is there a magic pin I can remove to confirm it’s not a kill switch messing me up kinda like the ac cdi pin.
#2
There are two different DC systems, and a coil with two wires, one of which is live with ign on, would indicate you have a 1980s car style 12volt set up rather than DC CDI. The blue/white will probably be the trigger coil, some have two wires, some use earth for the return, the green/white would indicate it is probably a two wire trigger. Green is usually earth. Black/red is usually the pos feed from ign switch. Black/yellow, negative pulse from ignitor (black box) to ign coil. They don't need a kill wire, as switching the black/red off cuts the spark, as in a car. Test those wires to the ignitor, trigger wires will produce a small AC voltage when engine is spun, and usually about 400ohms resistance. Actual values are not that important but open circuit or no resistance is bad, check if touching black/yellow pin on coil to earth, with ignition on, induces a spark at the plug. If all tests out as OK, but no spark when the engine is spun, it has to be the ignitor at fault
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Nedelec2493 (04-27-2024)
#3
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#5
Update
So black yellow had battery voltage 12.5 constant
red black no DV voltage but put it to acv20 and had .15
green is ground and had continuity
green white I couldn’t get dc or ac voltage out of it
black white had .44 at acv20
When doing a continuity test found .208 ( will upload picture) still no spark at the moment
red black no DV voltage but put it to acv20 and had .15
green is ground and had continuity
green white I couldn’t get dc or ac voltage out of it
black white had .44 at acv20
When doing a continuity test found .208 ( will upload picture) still no spark at the moment
#6
Blue/white and green/white will probably be the trigger wires so you should get a small ac voltage pulse across them when engine is spun, can be as little as .4v can be 4v or more. The black/yellow 12v pos reading is strange as it is usually the one direct from ignitor to coil, providing the negative pulse to coil. Disconnect it from both coil and ignitor and see if it still has 12v pos with ign on. If it has, it must be the pos feed from ign switch. This would mean the black/red feeds the black white to the coil which doesn't make much sense. If black/yellow is now dead, check if black/red and black/white have 12v pos on them with ignition on, this would make more sense as it would indicate they are the positive wires.
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