Sorry, I am not sure how to go back and add to my previous post... but it is kind of a new one anyways because I am posting a new issue.

So I have a jetmoto 110cc that I have had probs starting. It sat for a year or so I am told and I have yet to get it to start. I have cleaned the carb and think its getting fuel because the spark plug is wet and you can smell the fuel when trying to turn it over. I believe my problem is that it isn't getting spark... at least not the right spark anyways. When I previously posted I said it was because when holding the spark plug to the block I saw a spark... but I had someone else check it with me (someone who has actually looked at an engine before) and he said it's not sparking like it's supposed to. It will only spark at the beginning and end of pushing the starter button. And when I have gotten any 'running' out of the engine is only at the end of pushing the starter, so on the one spark that I get out of it.

Has anyone seen this problem? It has a new spark plug in it, so that shouldn't be the problem (NGK plug). I ordered a new voltage regulator (because it gets so hot you can't even touch it after 30 seconds of the key being on) and a new ignition coil to see if replacing those will solve my problem. But if there is any other info I should check or what to look for I would be very appreciative!

 

5 pin CDI or 4 pin CDI?

Are you sure about the single spark at the beginning of pushing the start button? That would be very strange... Single sparks at the releasing of the start button usually indicate problem with the timing trigger signal from the stator to the CDI.

Your "someone else" is right. At cranking speed you should see sparks occuring steadilly at about 10 times per second. Cranking speed is roughly 600 revolutions per minute (RPM), or 10 revolutions per second (RPS). Even the four strokes quads fire on every revolution (including the top of the exhaust stroke). This is because it makes the ignition system design much simpler, and it doesn't hurt anything.

The regulator sounds bad just like you surmised. You can just unplug it to do your ignition tests. The regulator has nothing to do with spark generation, but the starter will run your battery down, so keep an external charger (2 amps maximum) hooked up between tests so your battery doesn't get ruined by sitting around discharged.

 

Thanks Lynn - so do you think putting on the new ignition coil is going to help at all?

I pulled off the CDI and it is a 5 pin - I looked it up online to buy a new one... it was the first one I found so I think it is probably a very comon one, it has the 5 pin with the green plug. Should I just order a new one of those? They are only 12-15 bucks? If it's likely that that is my issue then I will go ahead and get it before waiting for the new regulator and ignition coil to get here and then having to wait for the CDI to be shipped too. OR do you think it is the stator? and if so how hard is it and how do you put a new one of those in?

Thanks again

 

The thing to do here is some diagnostic tests. Your symptoms could be caused by any of the things you suggested, and a lot more. It could be just a broken wire, or bad connection at a connector pin. The idea is to measure all the things that can be easily measured with a meter, and then use that information to steer us in the right direction. Meters are very cheap - and and incredibly powerful tool once you learn how to use it.

This is the generic procedure for troubleshooting ignition troubles on a Chinese five pin CDI:


Quote:
Is this a picture of your CDI?


Assuming the answer is yes, the first thing to do is eliminate all kill switches abd kill switch wiring:

Method 1) Unplug the CDI and remove the kill switch pin in the CDI connector on the wiring harness. The pin is held in with a spring tab on the pin itself. You'll have to probe into the connector and push this tab in order to extract the pin. Plug the CDI back in (kill switch wire dangling) and see if you have spark.

Method 2) Unplug the CDI. Turn on the ignition switch and set all kill switches to the run position. Use a meter to measure resistance in of the kill switch pin in the wiring harness connector to engine/frame ground. If the reistance is infinite on the 100K ohm scale then your kill switches/kill switch wiring are OK. If you measure zero ohms then you have a kill switch/wiring issue.

The other inputs your CDI needs to make spark are AC Ignition Power, and the Trigger signal. Do the following:

1) Unplug the CDI. In the wiring connector measure the resistance of the AC Ignition Power pin to the Ground pin. You should see 400 ohms or so. What do you measure?

2) Measure the resistance of the Timing/trigger pin to the ground pin. You should measure 150 ohms or so. What do you measure?

3) Leave the CDI unplugged. Set your meter to measure AC volts on the 100 volt scale. Measure the voltage on the AC Ignition Power pin to the ground pin while cranking the engine. You should see 40 to 80 volts AC while the engine is cranking. What do you measure?

4) Set your meter to measure AC volts on the lowest scale you have. Ideally this would be 2 volts but many meters don't go down this low. In that case use the lowest scale you have. Measure the voltage on the Timing Trigger pin to the Ground pin while cranking the engine. You should 0.2 t0 0.4 volts AC. What do you measure?

Now for measuring the output side of the CDI:

A) Leave the CDI unplugged. In the CDI wiring connector measure the resistance of the Ignition Coil pin to the ground pin. You should measure less than 1 ohm (but not zero ohms). What do you measure?

B) Plug the CDI back in. Set your meter to measure AC volts on the 20 volt scale. Set all kill switches to the run position. Crank the engine while measuring the voltage on the Igntition Coil pin to ground. Poke through the insulation of the wire if you can't probe the connector.

Caution: There should be moderately high voltage spikes on this wire. Make sure your fingers are not part of the circuitry. Don't touch the probe lead tips while doing this test.

What you should see is a lot of random numbers with lots of zero values as well. This is because the meter may catch all or part of the spark event voltage, with a lot of nothing in between. Describe what you see.

Note: Using a meter to measure this point produces highly variable results depending on the meter. What you really need is an oscilloscope, but most always a meter is all that is available. We have to do the best we can with what's available. Describe the meter results as accurately as you can - there is information there to chew on....