Hi Pete and thanks for reply.
Bike has around the 23000 klms mark. Oil usually ran at close to max.
Great explanation of the two causes, is there a thread on cleaning stepper motor?
From talking to a buddy, he reckons there would be no harm in running thru the Throttle body sync again but this time after a ride when the bike is properly warmed up.
I was above the 60 degrees last time but it was just from idle.
Suppose it would do no harm while I study up on stepper motor cleaning. Will look at that next.
Thanks again for the help all.
- Pete Roper wrote:
- How many Km has the bike done? Where do you run the oil on the dipstick? When were the TB's last removed and cleaned thoroughly?
High idle is usually caused by one of two things. A grubby, gummed up stepper motor or filthy throttlebodies.
Generally speaking, if correctly tuned, the stepper does very little and only moves within a very small amount of its range. That means if it does become loaded with oil contaminants pumped out by the sump being over-filled and then the tune is changed significantly, (By changing from having both air bleeds open to only one for instance.) it may suddenly be asked to move out of this very narrow 'Comfort Zone' and if it is significantly soiled it simply may not be able to compensate and the idle will remain significantly different from the required target.
If the throttle bodies themselves are filthy you can end up with the situation where when the TPS is recalibrated with the engine off and the throttle plates 'At rest' it will recalibrate to 4.8 just fine but when the engine is started the air pressure on the back of the plates will pull them around on the caked on crud in the bore of the TB causing the TPS value to increase. It won't do it by much but it doesn't have to. Once the ECU sees a value around or over 5.0 it will start advancing the spark. More advance and the idle will rise.