Make sure the piston and bore is within limits.
You need to hone the bore so that the new rings will bed in and stop blow by.
Do the proper heat cycles , let it idle to operating temp then shut it off and let it cool down for at least 30 mins.
Do this 3 - 5 times, re tension the head and then ride at no more tham 3/4 throttle for two tanks of fuel.
Others use a different break in technique, but this one is the most preffered.