bbk
 

if I get a 70 or 80 cc bbk will I have to change rollers, clutch springs .I just want more take off power with out losing top end.i weigh 185 and I would like better take off and I think more ccs is what I need

Yea if you keep the stock exhaust it should perform the same as stock but with more torque and faster up hills. Maybe slightly higher top speed.

You will have to upjet the carb and possibly adjust the needle position in the process.

depends on 2 or 4 stroke, if its a 4 stroke dont touch a thing unless you are going to get high end parts like hoca, the chinese performance clutches are off balance. the springs and weights are referred to as "contra" meaning when you change one thing in the drive system it contradicts something else. clutch springs will launch at a higher rmp, BUT they will no grab hard, the torque spring will get you better takeoff but it will kill your top end