depending on your weight a 125-200 could be an issue,70kg and less go the 200,a 125 you will struggle ,4- stroke are hard to master,people made that mistake 25 years ago when the Honda TLR250 came out,i would suggest a mid 2000 250 2 stroke and for starters put on the slow action throttle,if your ...

take it to a auto electrician see if he can test,could be CDI(more than likely cause its the dearest to replace)coil maybe,
give the Beta importer a ring