My aerox starts runs then cuts out

My son just got a 2011 aerox it's had engine mods it was running perfect then all of a sudden it playing up
It's start first kick runs for about 5 seconds then cut out it will start straight back up then do the same again
Any advice would help before I have a look

 

what happens if you give it throttle? might just need the tickover turning up, or the air screw setting right

 

or airfilter cleaned? check if its even there as if its been upgraded they kinda small you could of lost it or it got really wet

 

The lad said it still cus out

 

yh when i used to take my filter of my rox it used to bog and cut out straight

 

Ok I'll have a look on sataday if I get chance And thank u all

 

Sorted it it was the plug clean it and it ok now

 

And thank u for your comments