Guys...I need your help!!!!!!!!!

Can I just take my stock one to a parts store and have them match it up? Will a 2 stroke spark plug work in my 4 stroke 79cc?
 
If you have a two stroke plug try it, the plugs are generic. The length of the threads and the heat range matter. What you want is to find out if its firing with a different plug.
 
You can take the plug out of your lawn mower just to see if it firing, I've done that before.
 
I had one from my old 2 stroke laying around. Tried it. No fire. I took both plugs and hooked them to the wire and pulled...gave me a real nice jolt with each. It was dark out so I could see the blue spark on each. I did check each plug after trying to start. They were not dry so I believe I'm getting fuel, or at least some. I've cleaned the carb, coil and magnet, set coil gap, double checked timing marks, push rods are in the Tappets, and valves are moving up and down.

One thing I did notice is when I put my hand over the exhaust it wants to pop when I am attempting to start it. I can feel the hot exhaust gas come out as well.

I'm just lost! Short of buying new parts I don't know what to do. I hate feeling stupid...
 
Mike so what you are saying is the plug is firing but the engine won't "fire up" corect ? If that's the case I would recheck the valves to make sure the are closing, a compression gauge will do that.
 
Yes...I removed the spark plug and hooked it to the spark plug wire and pulled the pull start as if I was starting it. It was dark out so I could see the blue spark from the spark plug, and it gave me a real good jolt!

The only thing I've done with the valves is install 18lb valve springs. I set the valve lash. The push rods are in the Tappets and with the valve cover off you can see the valves moving. How do I check to see if they are closing? Dumb question...where do I hook up a compression gauge?
 
you checked the compression and its ok? then check the flywheel key to see if it broke or is even their. also some built motors dont like to start the first time, if you can find a go-kart starter to borrow, or try a big two hand drill with a socket.
 
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The compression gauge screws in the sparkplug hole in the head. Popping out of the exhaust sounds like a timing issue, if its out of time its firing when the exhaust valve is open.
 
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With both valves closed and the piston nearing tdc the magnet should be under the coil, depending on the specs it should be firing just before the piston gets to tdc. Usually °4 to °6 before on a lot of engines.
 
Here is the magnet with the timing marks lined up

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From what I can see it looks good, what do you have the valve lash set at? You can back off the valves a couple of thousandths just to see if it will start.
 
old motorcycle saying... ''a loose valve is a happy valve'' check stem height to make sure the valves are seated. no answer on the compression check.
 
Well guys...I've decided to pull the engine off the bike and start over fresh. I'm gonna start from ground zero. Pull the flywheel, redo the valves and springs, the whole shebang! Paying close attention to EVERYTHING! I had to of missed something and I don't want to play the guessing game and possibly ruin something else. It might not get done until this weekend, but it will get done. Hopefully Sunday...I can go into work when no one is there and work in the shop. I can also clean up the engine as well. Fingers crossed...
 
No I have not. I believe the coil is good because I have spark. With the spark plug removed from the engine and attached to the wire, when I try pull starting it I can see a nice blue spark and it gives me a REAL GOOD Jolt!
 
For what it's worth I say you are 180 degrees out on your timing ... pull gear .. turn 180 degrees too line up with the mark and reinstall ..... I think you'll be surprised at just how quik you'll be up and running again ...
Let me know how it runs when your done ....

** Ride with Pride **
 
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