No Spark, help please!!

[daveswfla53]

I have a 80cc 2 cycle that will not spark. When i first installed the motor it ran nice then after about 5 miles it quit no spark.
I have replaced all these parts 2 times the coil, magnito and magnito magnet plus the plug, checked all connections, added a second ground from motor to bike frame, disconnected the kill switch still no spark.
When i do get a spark it's weak then no spark.
Am i missing something?
Dave

 

[Pablo]

Sounds like something is fundamentally not wired correctly. Please give us details (pics help) of how it is wired.

 

[daveswfla53]

Black from magnito to black from coil
Blue from magnito to blue from coil
white no connection
Kill switch;
red and yellow to black
green to blue
this is the same wiring for the other 10 bikes i have built and they all run fine

 

[2door]

How are you checking for spark? Please give details. Your wiring is correct so lets look at the connections. Most of us abandon the kit supplied plug-in connectors in favor of soldered connections protected by heat shrink tubing. You say you have replaced all components but you didn't mention the plug wire. Take a close look at how it is connected both in the CDI and the plug boot. I'm personally not a fan of the kit plug boot and replace them with a good automotive quality boot with a copper cored wire soldered to the terminal inside it. Get back to us with what you discover, please.
Tom

 

[daveswfla53]

I'm checking the spark by plugging in the spark plug to the plug wire holding it firmly to the motor and pushing the bike with the clutch ingaged.
I have looked over all wires at there connections for good contact, have re-worked the plug wire to make sure good connection there also.
i also took a meter to all wires and not getting the readings that i have read here, not only on the bike with no spark but also 3 others that run perfect.

 

[2door]

Are you using the kit supplied kill switch (button)? Many have had bad experiences with these. They will sometimes be defective and close the circuit that grounds the ignition with the button not pressed. Just to test, disconnect the kill switch wires, if you are using one, and try the spark plug test again, or try to start your engine normally. If the kill switch is not in the circuit and you have replaced all of the components, magneto, CDI, spark plug, etc. then you need to inspect the magneto connections. There is a small solder connection on the core( laminated metal horse shoe shaped part of the magneto coil. Several members have reported finding that solder joint broken or non existant. Another point I've read but have not personally experienced is the magneto rotor, or the rotating magnet that affixes to the crankshaft. Some have discovered that it will not work if installed backwards. They say it is designed to go on the crank only one way. Try removeing it and flipping it inside out.
How far off are your ohm readings from what has been posted here? A few ohms is expected due to manufacturing differences but they should be 'in the ball park'. Keep us informed.
Tom

 

[Nnn]

I am having the exact same issue have no idea what to do as well

 

[crassius]

have you read thru all the threads on 'no spark'?

 

[Tyler6357]

CDI??

 

[Nnn]

As he said Dave said replaced the parts twice I have done the exact same thing(replace the parts twice and some even 3 times) and still nothing

 

[crassius]

I once saw two dead CDIs come out of the box, but that was many years ago and only happened once - I can't believe three sets were bad.

First, are you sure there is no spark? Hold plug in hand with hand against motor and pedal fast.

 

[Nnn]

I am 100 percent sure there is no spark. I first used the most famous method holding the plug on the engine and pushing the bike. Then I put a screw driver in the cdi where the spark plug would connect and put it near the engine so I should see some kind of electricity from the screwdriver to the engine and got nothing. I know the spark plugs work because I put them into an old weed eater and tested for spark and they gave out spark. I have used all these methods of testing before on other engines and saw spark from them

 

[Nnn]

I also tested all three cdis using a multimeter. I put the multimeter in the 2k ohms range and tested all of them. They all got NO RESISTANCE. It was like they didn’t even exist. And btw I have 4 cdis after getting some free replacements.

 

[crassius]

there is no way to test CDIs with a meter

mag coil should read about 350 ohm with a meter

one can't be sure there is no spark without holding plug in hand

you must be testing wrong or wiring wrong or something like that

is there anyone in your area that can look at this for you?

no start bikes are the easiest to fix - I get 6 or 8 a month and never spend more than 10 - 15 minutes getting a start or being able to point to the bad component

 

[Nnn]

That is interesting because people told me that I could test a cdi coil. I did test the magnetos and got 299 ohms on the 2 I have which I know is very low. My wiring is very simple I leave the killswitch out because I don’t know if it’s working. Then it’s just blue to blue and black to black. I did hold the spark plug in my hand if that’s what you mean and dint feel or see and spark.

 

[crassius]

CDI units have several capacitors that will read differently depending on which way the probes are on your meter - no matter what it reads though, the transistor that causes firing at the right time can not be read

to properly read the coil, one should test between the blue wire and a place on the motor that is grounded as well as to the ground wire itself

reading of 299 could mean you didn't dig your probe in hard enough or your meter battery is low or your stator is not on tightly with a clean connection to the case

absent a known to be good CDI, you may have several that are blown out - a couple years ago, there were new CDI units that lasted less than a couple minutes before blowing out, but haven't seen any lately

 

[Nnn]

1.im not sure what you mean by probe assuming it’s the wires coming out of the multimeter and the metal ends you connect to stuff for a reading
2.my battery is definitely not low in my multimeter it is brand new
3. Not sure what a strator is
4. I did test the cdis using the blue and black wires and got nothing

 

[Nnn]

Never mind figured out what a stator is and it is very tight to the case and I sanded and cleaned all connections.

 

[crassius]

metal often gets a bit of oxidation on its surface - to get good readings, one needs to press the probes into the metal (sometimes scratching the metal a bit) to get a clean connection - you know the stator is tight when reading between blue & black matches between blue and motor ground

 

[Nnn]

All I can say is wow. I somehow got my bike started with working spark now. I have literally no clue how this happened today it just decided to start having spark. It all ended quick though because now I have carb issues. The metal pieces the gas line attaches to on the carburetor now leaks and gas is also leaking in my carb but that’s for a different three thanks for your help