Why can't I get a spark from my plug?

H

hserro1221

New Member
I just put a 80cc 2 stroke engine kit on a bike and I can't get a spark from the plug. I think it might be the kill switch, if it is how do I bypass it?
 
How are you checking for ignition? How do you have it wired now?

If you suspect the kill switch (doubtful problem) then simply disconnect it from the blue and black wire. I say doubtful because they don't fail as often as suspected here. Usually the problem is something else like the spark plug boot or bad connections at the splices of the blue and black wires.

Tom
 
2door said:
How are you checking for ignition? How do you have it wired now?

If you suspect the kill switch (doubtful problem) then simply disconnect it from the blue and black wire. I say doubtful because they don't fail as often as suspected here. Usually the problem is something else like the spark plug boot or bad connections at the splices of the blue and black wires.

Tom
Click to expand...

Thanks for the response, how do I check if my magneto is good or not? If I hold the black and blue wire and pedal the bike should I feel a little voltage there?
 
You will only feel a shock from the sparkplug wire, wire the magneto to the cdi blue to blue and black to black with one kill switch wire to each, then cap of the white wire if you have one.
 
Do what Greg said then connect the spark plug wire to the plug. Lay the plug against the cylinder head cooling fins (the place where the wrench goes must touch the fins) and spin the rear wheel with the clutch engaged. If the ignition system is working you should see a spark at the plug's electrodes. It takes a good spin to generate a spark so spin the wheel as fast as you can either by hand or pedals. Of course this means suspending the rear wheel off the floor so having a helper might be a good idea.

Tom
 
2door said:
Do what Greg said then connect the spark plug wire to the plug. Lay the plug against the cylinder head cooling fins (the place where the wrench goes must touch the fins) and spin the rear wheel with the clutch engaged. If the ignition system is working you should see a spark at the plug's electrodes. It takes a good spin to generate a spark so spin the wheel as fast as you can either by hand or pedals. Of course this means suspending the rear wheel off the floor so having a helper might be a good idea.

Tom
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when I let go of the clutch the engine makes different sounds at random. Sometimes I can't hear the thumps of compression and others I can hear the compression thumps really clearly. But when I can barley hear it, it's way hard to pedal. Is this normal?
 
that's normal, but if it isn't all the time with clutch out, then your clutch is slipping sometimes
 
How fast are you going before you engage the clutch?
There will be a difference in sound with the throttle opened or closed.

Also did you follow the suggestions offered as to how to check for ignition (spark)?
If so, what happened?

Tom
 
Also a not so common problem that I have found in my buddies bike is that his bike won't run unless the kill switch is in. Even when disconnected it won't run unless the kill switch is pressed in.
 
YesImLDS said:
Also a not so common problem that I have found in my buddies bike is that his bike won't run unless the kill switch is in. Even when disconnected it won't run unless the kill switch is pressed in.
Click to expand...
You have a bad ground connection. Take a look at the black wire where it attaches to the magneto coil. If that connection isn't good then there is no complete circuit, until the kill switch makes one. While you're looking check continuity (ohm reading) of the coil. You might also have an open circuit in the coil windings (blue wire).

If the kill switch is disconnected there is no way the engine will run by depressing the kill button. Did you word that wrong?

Tom
 
2door said:
You have a bad ground connection. Take a look at the black wire where it attaches to the magneto coil. If that connection isn't good then there is no complete circuit, until the kill switch makes one. While you're looking check continuity (ohm reading) of the coil. You might also have an open circuit in the coil windings (blue wire).

If the kill switch is disconnected there is no way the engine will run by depressing the kill button. Did you word that wrong?

Tom
Click to expand...

Right I meant that when the kill switch is disconnected completely the motor won't run. I'll forward this information to him, but I think he is satisfied with his electrical tape fix ha!
 
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Below is what it should look like.
 

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Greg58 said:
Below is what it should look like.
Click to expand...

I have a spark now but the engine is making 2 different sounds when I'm pedaling. Sometimes it sounds like it's getting compression and turning fine but other times it sounds like there's no compression yet it's still hard to peddle.
 
Are you getting fuel to the spark plug? Do this, raise the choke lever then hold down the tickler valve on the left side of the carb for a couple of seconds. Then pedal up to 8 to 10 mph and release the clutch, continue to pedal and the engine should fire or "pop". It takes a little to get the correct choke sequence, you will have to find the one for your bike. If I doesn't fire or try to fire remove the spark plug and see if it is wet, if it wet you have fuel, if not check for fuel flow restrictions suck as a stopped up small filter on the fuel petcock or debris between the needle and seat in the carb.
 
Sounds like clutch is slipping. If engine doesn't turn over, it will not start.
You need to check your clutch adjustment to insure the engine is actually turning over when you release the clutch
 
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