To get everything together properly on your Pitbike 4 stroke single top end heres a few tips

Some Big bore kits have thinner head and base gaskets than stock
With these dont use the stock "O" rings
You may want to use a thin layer of Yamaha bond or honda4 semi drying adhesive

Set you Flywheel to "T" mark (top dead center)
then align you top cam sprocket mark to 9 o'clock

Adjust your tappets to .003" intake and .005" exhaust

Torque the head to 110" lbs ,run for a few moments then re-torque