Checking for spark and fixing a no-spark situation can be a little challenging. Electronics are difficult! I'm with you man, I have trouble with them too. But don't worry, we can figure this out.

Battery! You need a super strong battery! If your battery is weak, you won't get a good spark. Even if your lights come on bright, and your starter motor turns over, it might not be enough to produce a spark. Don't believe me? Watch this:

OK so now we are going to check for a spark. The quick and dirty way to do this is to pull a spark plug wire, jam a screwdriver into the sparkplug boot, and then hold the neck of the screwdriver close to the engine or the frame of the bike while you turn over the motor. You should see a thick, blue spark leap from the screwdriver to the frame of the bike. If it is yellow, thin, or nonexistant, then you have a spark problem. Also you can use a spark tester like this one, just plug it inline with your spark plug wire and watch for the light.

Remember! Even if you do have a spark, you have not yet tested the spark plugs. They may be fouled, wet, corroded, damaged, gapped improperly, etc. So keep that in mind. But, lets just assume you didn't find a spark.

OK, so no spark. The engine turns over just fine, but no spark.

First, look for any safety switches which might be causing this. Many bikes will have switches on the kickstand, the clutch lever at the handlebars, or on the neutral button to prevent you from starting off accidentally in gear. Sometimes these switches ground out the spark circuit, and sometimes they work in the opposite way by completing a circuit. Here is more information on that:

Along the same lines, sometimes your killswitch can fail. Most bikes, if the killswitch fails then the starter button won't work either, but some bikes allow you to rotate the starter motor but it grounds out the spark. So, take that apart, clean it up, and see if that can help fix your spark. Killswitches work in the same way, either breaks or completes a circuit, so if you suspect the kill switch is to blame, cut the wires going to it and then test. Still no spark? Twist those cut wires together, effectively cutting out the killswitch, and test again. If you need help diagnosing these simple switches, check out my wiring diagram video:

Also consider the possibility that you have good spark, but it is escaping. This means that the spark is grounding out to the frame or motor without traveling to the spark plug. Something I do to check for this is to turn over the motor in the dark, looking for the little spark. If you see it around the plug wire, plug boot, or wherever, then you know thats your problem. The repair is new spark components.

It is also possible that the problem lies in a dysfunctional component of your ignition system. Motorcycles generally have two different types of ignitions, electronic and points ignitions. The points system is much older, you'll see it in your old CB550 for example. Electronic ignitions are in most newer bikes, and feature a "black box" or CDI which controls ignition timing.

So, which type do you have?

Electronic

Points