Jumping around of rpm

[oprider]

Hi all, check with those have true life experience and remedy for below:
- unstable rpm and speed at constant throttle, got some backfire too.
- idle speed at the region from 1200-1500.
- a drop in rpm (~200rpm) during intial pulling of throttle from idle.
Have done the top service, changed plugs, serviced injectors, synchronize TB.

 

[Checkswrecks]

Did all this only happen after the service?
I'd start by looking into possible vacuum leaks, especially at the rubber nipples which get removed for the TBS.

What year bike is yours?

 

[oprider]

Last item surface up after service.
Year 2011

 

[oprider]

Just came back from a change of TPS. A lot better now.

 

[2daMax]

Erratic idling is usually found to be caused by either :
1. bad plugs
2. ignition coils.

 

[Checkswrecks]

These bikes and many others also have a history of intermittent vacuum leaks of the rubber caps at the bases of the throttle bodies. Do a TBS and you at least re-seat those and it's a good idea to replace the rubber caps from time to time.