thanks. sorry i took so long to respond but i am not going to use the crf50 because motorcycle engine on a bicycle are not permitted here in Colombia S.A. unless it has a frame and engine vin on it and new for registration. would like to construct my cub90 with big wheels 21" and 18" wheels and motocross suspencion but that would be in a diff form i guess. i have this board tracker motor bicycle that im building.