rjs9s

ok so i have this habbit of hitting the rear brakes wen i go past bp. i dont know if im slamin the brakes or what but everytime i do so even in first gear on my kfx 400 the front slams down and almost flips me over the bars. im only about 100 lb. maybe thats the reason? and also wen i scrape the bar i slam the bar. i dont know wat im doin wrong here but i already broke 2 screws int he 12 bar lol. maybe its the fact that i need a new cluth cause i have none left and i cant just slip it or anything???