Fast Idle Screw and Temperature

I have an 02 GSXR 1000 and when I start the engine cold I can see that the fast idle screw engages but then disengages after a few seconds and the idle screw kicks in and sometimes the engine stalls. I can see all of this because I propped the gas tank open to see what was happening with the fast idle and the normal idle. My question is should the fast idle disengage so quickly OR only after reaching a normal operating temperature. If it should reach a normal operating temperature what would be my problem since the fast idle disengages after a few seconds after a cold start. Bike runs fine once it's warm.

Don't know about that bike but on a Kawasaki ZX10R with similar throttle bodies, the "fast idle" is via a linkage from the secondary (servo operated) throttles which cracks open the main throttles slightly depending on the position of the secondary throttles. I don't think the Kawasaki system is adjustable but I could be wrong. (Never had to touch it - hasn't been any need)

The programming of the secondary throttles, and how they are used on cold start, is programmed into the ECU. It is at least somewhat coolant temperature dependent but I think this is only for their initial (fast idle kick-up) position, and the ramp-down after start-up is timed.

Is your warm idle speed set too low?

Is your engine oil too high in viscosity (too hard to pump when cold)?

If you have a Power Commander, is your idle set too lean? One trick to keeping the engine idling without causing a rich hot idle is to add a bit of fuel in the 0% throttle column just *below* normal idle speed ... that way when it comes off fast idle and tries to stall, the PC gives it a little extra fuel to help it stay running.

Valve clearances - spark plugs OK?

If you have the ability to adjust the fast idle kick-up linkage, can you adjust it? If the computer is commanding the secondary throttles completely closed within a few seconds of start-up then this won't work, but if it is going to an intermediate position (and the idle kick-up is not in contact with the tab on the main throttle linkage) then it might.

Hey Brain, thanks for the detailed response. The warm up idle is around 1500 but after about 2 or 3 seconds it drops to around 800-900. When the engine is warm the idle is around 1000 +- 100. I might try adjusting the warm idle to set it a little higher. What I have been doing is holding the throttle a little and giving it a little gas to keep it from cutting out, again, does not do this all the time. I'm using 10W/40. I don't have a power commander and last summer I had the spark plugs changed done by a shop. I'll take a closer look at the positions of the contacts and that tab. I'll also look into the ECU bit. Thanks again.

Your warm idle speed is set too low, and that's likely why it's stalling. The specs should be in the book. In the absence of specs, try around 1300 rpm.

I have a 03 gsx-r600 with the fast idle lever. on cold starts I turn it on and the rpms do not drop, they actually get higher as the engine warms up. so yours is not acting like normal.

your normal idle when the engine is warm should be around 1300rpm

Does the op's gsxr1000 have the fast idle lever?