Frustrating experience; am I stuck with a bad motor?

Spark itself is easy to check, simply remove the spark plug from the engine, but leave it connected to the wire, ground it against the engine lift the back tire and give it a bit of a spin, you should see a healthy blue spark, if you have that, and compression, then you can move on to spark timing...
 
Check for spark in a dark location because you probably won't see the spark or it'll look very weak in the light
 
Wyvern said:
What does the jug/piston look like?

If you have compression and no scoring, it will run, if it still doesn't, it's electrical, coil rotor not timed right, kill switch broken etc.

Extremely simple engines, but everything needs to work.
Click to expand...
I agree 100%. My first engine I ran it for 5 minutes and it locked up because of a piece of casting (I hadn't done enough research to know I should of tore it down and checked for the extra metal). It took me 3 weeks after I got it unsiezed to figure out I had lost the woodruff key lol.
 
Thank you all for responding; I apologize for not answering sooner, I have been away from my home to help a family member who has been extremely sick.

I took the entire engine apart when I first received it and checked on everything and it seemed to be okay. I've not seen any spark but I don't have a garage and the bike doesn't easily fit into my cabin; however, I did measure the voltage and/or resistance on the electrical items and, according to some posts I'd found on an Internet search, they were within tolerance.

I have not checked compression. I'm not sure which compression tester I should use. Can I pick one up at the local parts store and use it on these engines?

I'm going to install the engine on another bicycle frame (a Schwinn OCC Stingray adult size), so I may bring the engine inside, clean it up (it's been outside) and re-check everything. The current frame is difficult in that it has extremely low tolerance between the rear wheel and the frame so that the chain is rubbing on one or the other. Since it is aluminum, I can't bend the frame.
 
wiserak said:
Thank you all for responding; I apologize for not answering sooner, I have been away from my home to help a family member who has been extremely sick.

I took the entire engine apart when I first received it and checked on everything and it seemed to be okay. I've not seen any spark but I don't have a garage and the bike doesn't easily fit into my cabin; however, I did measure the voltage and/or resistance on the electrical items and, according to some posts I'd found on an Internet search, they were within tolerance.

I have not checked compression. I'm not sure which compression tester I should use. Can I pick one up at the local parts store and use it on these engines?

I'm going to install the engine on another bicycle frame (a Schwinn OCC Stingray adult size), so I may bring the engine inside, clean it up (it's been outside) and re-check everything. The current frame is difficult in that it has extremely low tolerance between the rear wheel and the frame so that the chain is rubbing on one or the other. Since it is aluminum, I can't bend the frame.
Click to expand...
you can get a compression tester from a parts store, yes. They are pretty universal.

Aluminum frames aren't advised for motored builds, so it may be a good thing that you are moving the engine to a different bike.
 

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