Tvs Motor Company — kick problem

My 5 year heavy duty bike wb 34 ak 3330 kick rachet slip 5-6 time within last 1 year. I change it every time with original brand new cost 350/- +250/-other cost but it lasting for about 2-3months every time. As per mechanic suggestion i change its clutch chember (850/-) and kick shaft (350/-) but my bike is not ok still now. Many mechanic are failed to repair and they said there is some manufacturing defect in the engine. I also thing same, otherwise one mechanic can fail but all can not fail in one case. What should i do now? Plz help me. Thank you.