ok, understand. soft tuning is ok. realy you can make any on cvt(light weight), better exhaust pipe (more torque). you can realy reach 1-3hp max, if you perfect adjust carburator. not more.
linhai is fine, you must live with. if you want more, buy better any with more power. i have for expedition many 300cc ATV and it is ok. then i have Gamax 600 (42HP) and Kingquad 700 (49HP)... is little bit better. you dont need make tuning on engine. but i changed suspension.