Savage3

Hot tip, a bad sensor does not create popping noise. Also, the crank sensor will not know the chain has skipped a tooth. If you want to test the sensor, I'm sure the service manual has specs.

Ok, so we go back to his original post. I was basing troubleshooting on this post . The popping sound is important. If it has fuel, spark, and compression ( assuming he made sure fuel is reaching combustion chamber and it's fresh) I would personally check timing next. The last one I rebuilt, the chain tensioner had a total meltdown with only 200 hours. Same symptoms as described.

The original post states that the machine has fuel, compression, and spark. With a Hisun, low hours or miles means little to nothing. I've had to rebuild top ends on basically new machines due to overheating among other issues. These machines are riddled with problems. I wouldn't assume anything or overlook any possibilities. If the machine has fuel, spark, and compression, logic points to the machine sparking at the wrong time. Merely food for thought.....

Remove cam cover and inspect, see if timing marks are lined up. Also look in hole on bottom case to see if the timing mark is lined up. See if chain still has tension as well. Piston should be at top dead center compression stroke when timing marks are lined up. I have seen the chains get loose and they skip a tooth or two. I don't understand how it does it, but, it does. Changes timing and pops out intake.

If you have fuel (fresh fuel), spark, and compression, I would look at timing. Is it sparking at the proper time? Is it possible the timing chain was loose causing the pop noise?

Please remember, just because you replaced the parts, that does not necessarily mean they are functional. (Even if they are brand new) You must systematically test each component after install. Verify each component is within spec taken from service manual. Attention to detail is paramount. Ya can't cheat a single procedure. Start at stator, verify. Then pulsar, then CDI, then coil, then plug. Start at battery, check voltage. Is it A/C CDI or DC CDI?

What was the air gap set at on pulsar coil? What is the peak voltage that the pulsar is generating?

What is the year make and model?

In effect, the pulsar coil is the crank shaft sensor. It tells the CDI when to spark based on the position of the crank.

Interesting, the rest of the cage bearing must be in the case. Not good! Did you drain oil from engine when you found cage in spout? If not, do so and meticulously inspect oil for foreign matter. Did you turn motor over several revolutions by hand? Did you hear or feel any grinding or resistance? Remove spark plugs prior to test. What is voltage at signal wire of starter when turning key to start position. You may have two issues, electrical and mechanical.

Put wrench on crank, turn engine manually. See if it is seized.

Oh, thanks for the update. I thought it had carburetor. My guess would be poor quality gas. Usually only takes a few weeks to create problems if it is ethanol. I would purchase new gas, not from a can on your garage. Winter blend non ethanol would be the best option.

One thing I forgot to mention, try fresh gas, non ethanol if you can find it in your area.....drain the old gas out. Use new gas, about a teaspoon in cylinder. I never use ethanol in small engines, stabil is not the best option either, try Startron

Ok sir, check valve adjustment. Sounds like they may need adjustment if you were struggling at 40 degrees. Prior to that, I'd put a little fuel directly in cylinder through spark plug hole and see if she pops off. Let us know the results

How did you determine the cylinder is getting fuel? Let us know the specifics of your troubleshooting steps thus far.

If magneto didn't work, check trigger coil at stator, check coil, then look for grounding issue. Review service manual that Travis posted above for specific testing/troubleshooting procedures for your model. The manual provides step by step guidance.

Check spark while it is running and when is dies sir.

Make sure battery is fully charged while testing!

Disconnect kill switch, crank engine, see if it starts or at least has spark.

What is the voltage reading? What is the resistance reading?

Yes sir, that's what I was thinking. The compression test followed by a leak down test will illuminate a valve train issue. Make it easier to nail down the location of the problem.

Start by checking compression, then timing

Read page 319 of the service manual I posted earlier. It's also called a pick-up coil, pulsar coil etc....

I haven't viewed the service manual for your model. However, oftentimes, they call a crank sensor the trigger. This coil is located right beside your stator. Usually has a blue wire, sometimes a green wire as well. The ones with only a single blue wire ground to chassis.