I have been fighting this sunl 110 for a couple of months.
After replacing the coil, battery, starter and carb I can sometimes get it to run for a couple of seconds.
The problem I'm completely stumped on is a starter noise.
Here is a video


The first few seconds are right after the motor died after running for 10 seconds or so
Then the second part of the clip is after I backed out the spring loaded throttle barrel adjustment just a bit.

If I try to give the bike throttle while starting the chattering noise starts.
The second part of the video you can clearly hear the motor spinning, whereas at the beginning the motor isn't turning over.

Again the only change is backing off the throttle adjustment

 

Starter clutch bearing. I had to do this on my Dinli I sold a few months back. I found a kit on ebay.