Idel rpm jerking?

[Testname111]

Is this jerking/almost back spinning the crank?
But is this due to idel suffering from a jet to big? Using a #75 jet in a HP carb/Rungtun? Stock is #70 jet

 

[Larry Trotter]

lower the pin all the way down and see if it gets better.

 

[Testname111]

I'm just rebuild the whole engine with hybrid ceramic crank bearings and a home made copper wire crank gasket!!!

 

[Testname111]

I want longer life!!!!