hi, i have a cHonda crf50 that the shifter just keeps rolling over. i'm wondering if this is normal for this bike or is there a part broken/missing. i've owned several bikes, this is the first i've ever rode that did this. all of my gears are down, with neutral at the top. if i shift higher or lower than neutral or 4th, there are no shift stops. hitting neutral with high revs annoys me, as does going from 4th to first. any help is appreciated.