Picked up a 110 for my son last year. Carb was too bad to rebuild, so we ordered a new carb and ended up getting one that hemorrhaged fuel. During this time the quad had great spark, just a carb problem.

Fast forward to now. I decided to get it up and running recently. Had to remove the engine to weld the rear motor mount. Put the motor back in, and I have no spark. Below is what I've checked.

Tested the wires at the cdi harness with the cdi unplugged.

Trigger wire to gnd was 111.5ohm, and when cranking the voltage was .2v, when tested with an led tester there was no light

Ign Coil to gnd .2ohm and 0v when cranking. Just a quick spike when I 1st hit or release the start button.

Kill wire is disconnected at the cdi harness, also tried with it pulled at the engine harness too.

AC Ign to ground, I cat remember the exact #, but it was in the 350ohm range earlier, and cranking voltage was 58-59v, but now the resistance just does a quick spike on the meter, then goes to 0

Also measured the voltage at the black/yellow wire running to the coil, and got nothing. Just an initial spike, then 0.

Any ideas on what I should try next?

 

Update. I now have spark. It was a loose connection in one of the harnesses. New problem now though. Confirmed that I have good strong consistent spark, and it's getting fuel, but it still wouldn't start. Didn't sound like it was trying to at all.

I stepped around to the other side of the quad and there were random sparks coming from the top of the coil when cranking. Literally sparks from the top of the coil opposite the plug wire. It was the coil itself arching, and not the wire.

I've never seen that before, and I'm not really sure where to go from here. I have another coil, but I've been unable to find it. If I come across it, I'll try it out, but is there anything else that could cause this?

 

Found the no start problem now as well. Compression is only 40psi.

 

Oh how I long for the days on Honda and Yamaha in the garage. Seems like every time you track down a problem with one of these chinese quads, you just find 2 more.

I decided to adjust the valves and do another compression test, then do a wet test to see if the rings are the problem. I adjusted the valves, and went to crank it and got nothing. There's power to the solenoid, but no crank. Even jumping the solenoid doesn't do anything. I even ran power direct to the starter and got nothing at all.

 

If you are sure the battery isn't flat it must be either a bad earth or the starter gone. Make sure the earths are OK and open the starter to check if brushes are worn out or stuck. A long lay up can cause brushes to stick, or all that cranking could have overheated the windings.

 

No battery, I'm jumping it off a car. I got it to crank, and now after adjusting the valves, it's got 0 compression. Wondering if I had it tdc on the exhaust stroke instead of compression.