hi, i have a similar starting problem. look up under general discussion, ie jawa 210 49cc 2 sroke. mine just died on me, when it got difficult to start, after leaving it for an hour. i also give it a a tear drop of easy start, starts instantly. i fitted an nt 49cc carb. drilled a small hole about 1/4 inch, just to the right of the filter, found a rubber plug. to push in the hole. quick and easy, for emergency. i carry a small plastic eye bottle with me, to fill it, spray some easy start into a cap of some sort, then get the eye bottle squeeze it and suck up the easy start. you do not need much in the bottle. a tear drop usually works. i call it a mechanic in a bottle. assuming your engine and electrics a normally very good. Unfortunately it no longer starts mine.
i think i have a stator problem, no spark, i fitted the new type thyristor with the built in coil. 3 spade tags. red wire on the G then yellow, on the I and a white one on the other I POSITION, hope this is correct. but no sign of a spark. i use a ngk b6hs plug. never given a problem. fitted a new HT lead, and cap. waiting for some test equipment to test further. removed the cut out switch, still no start, going to fit a new on off switch, better than the orginal. Any ideas how to test the stator??