Zip 70cc stage 6 starting issues

hi guysGot an odd one here, new 70 kit as old piston blew up, new carb, exhaust, rollers, jets etc... bike struggled to start for a good hour then it sparked up and ticked over perfectly, throttle was on point, no bogging etc. But I did t get a chance to ride the bike as I turned it on and off numerous of times, then got all ready to go on, started it then it bogged under throttle then cut out?? changed fuel, checked fuel lines/oil. Anyone have any idea??

 

Why did the old piston blow up?
Whats the jetting like?