I just want to say that the xr 100 is a great bike. im 12 years old and i ride it all the time. I have no trouble with my xr. just normal bike work like chain and sprockets, flat tires.....exc. With maybe a grand put into it, it will fly!! my bike honestly does about 80 and i havent put very much money in to it.i was wondering though does any body think it would make a nice pit bike? i noticed the 50´s with the 100cc engines in them and i wanted to know am i able to put a 200cc engine in my bike well if you know the answer or have coments leave :-)