Deserately need help w/Sputtering 00'

THis one has been to the dealer 4 times and is still not fixed. Problem started as a gradual powerloss between 3500 and 4000 rpm. Later progressed to kicking, sputtering and power loss to a level that left the bike unrideable below 6000 RPM. Now the dealer has: changed the plugs and air filter; checked the EFI and stator and used injection cleaner. They claim the bike runs fine even though there is still sputtering and a loss of power below around 4200RPM. Anyone have any ideas?

Also, should I have them reload the EFI mapping on occasion?

Thanks in advance for any suggestions!

 

Im experiencing the same thing right now. Im thinking fuel filter but I dont want to take out the fuel pump without knowing first. Anyone have any idea? Im going through riding withdraws please help :'(

 

Check out VFR discussion group. This subject has just come up.

http://www.vfrdiscussion.com/forum/index.php?showtopic=14688

Ian