I just finished rebuilding this unit last Sunday. I had replaced the piston head, gaskets, cylinder, carb and cylinder head with valves. Well as I finished it up, I was excited about refilling the fuel tank verifying all the connections and going for a ride. All that came to a hault when I turned the key, sat on the quad and opened the fuel line and it spun the starter, however it would not engage. I pulled the spark plug to make sure I had a spark and it did not. It is a brand new spark plug, the battery is fully charged, fresh fuel. Am I missing something?

 

Let's make sure I'm understanding this correctly... Your starter spins freely, but the engine doesn't turn?

If so, the first thing to check is whether you installed the battery backwards. If you do the starter engaging wiring will still work, but the starter will spin backwards. A backwards spinning starter will freewheel at the starter clutch and never engage the engine.

 

The battery is in correctly. Made sure today when I verified the charge. Put it back in and tried to crank it. It is spinning. I think the problem is that I have no spark from the plug which I replaced today with a new one. No spark!

 

I guess I've been misunderstanding you. There is a clutch between the starter motor and the engine. If that clutch isn't "engaging" the starter motor will spin but the engine will not. That is what I thought you were describing.

I'm still not 100% clear. You responded that "it" is spinning . The engine? Or just the starter? What is *it*?

If the engine is actually turning, but just not starting, and you have no spark - then we need to know whether you CDI is AC powered or DC powered. I'm going to make the assumption that you have a six pin CDI. If not we will have to back track a bit...

Here is the procedure for determining which CDI you have. The procedure from here varies between AC and DC CDI's...

 

Sorry to mislead you. Yes the starter is spinning. Let's start from the beginning. I purchased this unit from my brother in law several months ago. When I brought it home he said, "all it needs is a battery". . So I purchased a brand new battery equal to what was in the unit. As soon as i charged it up fully. I placed it in the holder and try to turn it over. It would not, someone from this forum mentioned I would need to remove the carb and clean it out. I purchased a gallon jug of carb cleaner. I let the pieces soak overnight in the cleaner. The next day, I removed them and let them dry out. After re-assembly, I noticed the smallest jet had some blockage. I tried some many different ways to remove said blockage and it would not come out. I drove to several local repair shops for atv's and they said good luck with the Chinese quads. One guy said that he would use a 3/16" drill bit and try to remove the blockage. I did that and it came out, maybe with a few little pieces of metal. I placed back back in the carb then put the unit back in place on the quad. As soon as i hit the start button it started and the rpm's were extremely high. I also noticed the exhaust pipe was glowing bright red. I believe these are signs of too much fuel. I tried to quickly adjust the carb screws for air and fuel and it was too late. I heard a thud it the unit stopped and would not restart. This is now where I started to use this forum . I received a couple of responses to remove the valve cover , the valve assembly and the cylinder. i did just that and noticed a hole in the top of the piston. Now we come to the part where i have replaced over the last few months the parts from above. Why would it now not spark? I wish i could attach pics to these posts so that you could see what happend and what I have accomplished.

 

when you click, post reply, in the command box you'll see the paper clip symbol for adding attachments. on your computer you should store your pics in a certain folder, then after clicking the paperclip symbol, go to that folder, double click & upload that/those pics. if that still doesn't work for you, make an album under your profile. that's located bottom right hand side. we can go there to look.

so you've rebuilt the engine and now no spark.
red exhaust pipe means it is running too lean, excessive RPMs at start up could've been the result of excessive lean condition, throttle slide installed incorrectly, throttle cable stuck in the wide open position.

 

Yes I have rebuilt with original parts. The battery is fully charged. I have fuel and no spark from the plug.

 

I am not sure I am following the instructions for the CDI. If I disconnect the plugs how will it show any voltage?

 

The first time I try to start my ATV, the starter spins and then stops. There is a part just to the left of the positive terminal of the battery
that clicks alot when I push the start button.

 

Let's start here since this is fundamental. I think you are describing the starter solenoid. Your starter motor draws a *lot* of current to spin up the engine and make it start. On your quad it might be a high as 50 amps. A switch that can handle switching 50 amps is big, and has to go "click". Your teeny little start button (or ignition switch, or whatever), cannot possibly pass this enormous current. Hence the starter solenoid: The solenoid has four connections: 2 big screw terminals (usually) which pass the enormous starter motor current, and two little actuating wires. When you apply 12 volts across the two little actuating wires (which comes through your little start button and a host of other circuitry), it drives a coil of wire that generates a magnetic field, which sucks down a steel plate, which shorts together the two big terminals together. This connects your battery directly across your starter motor, and makes it spin the engine.

But you see? The teeny start button switches just a few amps, which in turn switched tens of amps...

Cars have starter solenoids too... For exactly the same reason.

Solenoids that "click" but don't turn the starter motor usually indicate a discharged or faulty battery. Take a meter and measure the DC voltage right on the battery terminals *while you are attempting to start the quad - i.e.solenoid "clicked" *. What do you measure?

I'm going away for ten days. I won't be able to reply til I get back...