STV and Fast Idle

This is just an FYI for the curious

It's a short video and animation on how the Secondary Throttle Valve Operation also controls the automatic fast idle on start-up.


Doing a service and tune up on the GSXR and I thought I'd video the automatic fast idle set-up. No real reason, I felt like it. Crude but it does the job. But I miss having a bar mounted lever so I have some control. (And it's a pain that the idle adjustment screw is only accessible when the tank is lifted.)

When the ignition is turned on, the ECU fully opens the secondary throttle valves, connected to the shaft is a set of linkages that move the fast idle screw that lifts the throttle off the normal stop.

Depending on coolant temperature, time running etc, the ECU then closes the secondary throttle valves and normal operation happens.

It doesn't matter that the secondaries move the fast idle screw when you're on the throttle, because the butterflies are not on the normal stop anyway.

This is an animated gif of the operation - click for a larger picture.
(Two frames, 3 seconds each.)

This file is hosted by wotid.com

4.8MB WMV file (I thought my old TLS was an easy starter)

This box might be blank until the file downloads
Right click here, 'save-as' to download the WMV version.

If you can't view WMV video and want to see it, I have it as a 4.8MB AVI file too. Right click 'save-as' to download the AVI version.