How Do I Get My Aprilia Rs 125 To Start?
 
                i have an aprilia rs 125 2000, 
everytime i try to start the bike by using the electric start button, nothing happens, it seems quite lifeless, however it backfires. if i bump start the bike and can keep it running above 3500rpm shes a beauty, but as soon as i let of the throttle and it drops below, it cuts out straight away and sometimes wont bump start at all afterwards. 
i have cleaned the carb, jets, airfilter, airbox, tried using the tick over screw to adjust and different settings on the carb needle. i earthed the spark plug and it seems okay. nothing works!
PLEASE CAN ANYONE HELP?
            
             Trickster019
            
 April 2010