you are joking right?
do you know how the engine works? So simple and can be stripped down, take engine in the house (they're that light and small) replace apex seals, that's a rebuild. Then put it back in.
people think they are normal petrol engines and f**k them by letting it get low on oil and burning the seals out.
they are so cheep to rebuild if you do it yourself. Its people like you that don't now how it works and listen to the bullsh!t from so called specialist that can charge a fortune.
they are bad on short runs and can flood or build up carbon.
great engines if you know how to look after them.