tps or stepper motor?

I have an 07 classic with 29k on it. A new secondary tps was installed with 19k on the bike in oct. 2010. the bike has ran and started perfectly since then. Now, when i start the bike, it idles at rough 650 rpm with no increase in rpm. If I turn it off and then start the bike right away it starts like it always has (revs to about 1000 to 1200 rpm and then settles to an idle of 850. I have watched the stepper motor when i turn it on and it seems to work ok. The piston pushes out a little and then the piston pulls back toward the stepper motor a little. As I said , when I start it for the second time it idles perfectly(850 rpm) and runs great. I only have an issue with it starting the first time.

thanks
MarkC

Mark I got your message but am not home yet. So lets think out loud. Secondary TPS are you sure they cahnged that or did they change the primary TPS?

If you know which one they changed we can sort this out. If it was the one on the back of #3 throttle body then it was the primary TPS. If it is on the #1 throttle body rigth aboce the throttle cables then it was the secondary TPS. Did they do a full Idles Stepper Motor Control Reset? Do you have Tune Boy for the bike?

If you're familiar with the TPS, you can take off the head, & look at the colour of the teeth in it. The upgraded ones are blue,( old ones black). Resetting the ISCV ( Tuneboy or tuneecu) is necessary from time to time,& should fix your idle.

From the part number he sent me they did in fact change the primary TPS not secondary. They must have just told him wrong by accident. I have not heard back from him but informed him of the need for a ISCV reset. By either Tune boy, pr the other tuning aid. Only other option is the Dealer that did not do it anyway. This IMO should be done when ever you change the TPS as it retracts the stepper motor fully before having you check the Voltages. Then if memory is right it extends the stepper motor so you can check for the .12 voltage increase. These steps are important so that everything is in sync with the ECU. The ecu uses the TPS postions along with ambient pressure sensor, the air temp sensor, and engine temperature to calculate decide how much extra throttle is needed for idle.

In some cases after miles and miles the linkages get worn and the butterfly is shut more then when it was new. Mine hade this problem at 56,000 miles the throttle was closing to much. I adjusted the close throttle position and then reset sensors and idle stepper motor by performing a full ISCV restet via Tune Boy.