thanks for your help
Its all very interesting' had a look at the link' my setup is exactly as the picture i posted so need to do more digging around i think. As to the controller i wouldnt no where mine is.I'm interested in changing the sprocket though i have found something on ebay that looks ok have a look see what you think
http://www.ebay.co.uk/itm/BMX-FREEWH...item5d2c06a72b