last season i used the started but it didnt start like 50cc it takes few secund to start...now i pulled the starter out for more rpm on the crank and i use the kick starter all the time...
From what I've been told, you can over vault the starter to make it work on 70's kits... Sounds dodgy to me.
Kick start is just the way to go at the end of the day if youve got a 70s kit, that way it cant go wrong unless somthing shears in the kick start mechanism.