Hi guys i was riding the xr200 one day, the next it just wouldnt start at all. i have tried a new sparkplug ive tried run starting it but to no avail. what happens is the bike starts but only when going down the hill and at a very quite pitch and when i apply throttle nothing happens, theres no change in revs or sound and when i get to the bottom of the hill it just dies. does any one have any useful advice it will be much appreciated cheers. xr rider paul.