Hi am new to this and have a few questions. i all ready searched around and still cant find any answers.i want to build a Mountain Bike with the biggest 4 stroke engine possible i think 80-100 cc is good. i have this GT bike but dont know were to start. whats the best engine i can buy and would like to be able to shift my rear de-railer on it gears while i accelerate so i dont want a big sprocket in the back i want the engine chain to go to my crank and still be able to peddle it with the engine off. i also would like to put disk brakes both front and back and i would like a better gas tank design instead of that common teardrop shape one. if anybody can tell me were to buy everything i need and the best engine for my needs i would really appreciate it. i live in NYC so i want something that will roar down the street like a dirkbike and look and sound illegal and practicable for mild hills i would like to have it able for some jumps but i would need a full suspension bike for that if there's any tips please let me know am lost and dont know were to start. i also dont know how to post pictures i have a few of my bike. would share with anybody if i knew how to show them if anybody can show me that too